137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

CSC-201 - Computer Science ILecture 5 Chapter 7

Dr Chuck CartledgeDr Chuck CartledgeDr Chuck CartledgeDr Chuck CartledgeDr Chuck CartledgeDr Chuck CartledgeDr Chuck CartledgeDr Chuck CartledgeDr Chuck CartledgeDr Chuck CartledgeDr Chuck CartledgeDr Chuck CartledgeDr Chuck CartledgeDr Chuck CartledgeDr Chuck CartledgeDr Chuck CartledgeDr Chuck CartledgeDr Chuck CartledgeDr Chuck CartledgeDr Chuck CartledgeDr Chuck Cartledge

September 21 2016 at 910amSeptember 21 2016 at 910amSeptember 21 2016 at 910amSeptember 21 2016 at 910amSeptember 21 2016 at 910amSeptember 21 2016 at 910amSeptember 21 2016 at 910amSeptember 21 2016 at 910amSeptember 21 2016 at 910amSeptember 21 2016 at 910amSeptember 21 2016 at 910amSeptember 21 2016 at 910amSeptember 21 2016 at 910amSeptember 21 2016 at 910amSeptember 21 2016 at 910amSeptember 21 2016 at 910amSeptember 21 2016 at 910amSeptember 21 2016 at 910amSeptember 21 2016 at 910amSeptember 21 2016 at 910amSeptember 21 2016 at 910am

237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Table of contents I

1 Test Results

2 Schedule

3 Miscellanea

4 Control Structs

5 Addrsquol Operrsquos

6 Break

7 Hands on

8 Q amp A

9 Conclusion

10 References

11 Files

337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Histograms

Histogram of questions and misses

437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Histograms

Histogram of letter grades

Test scores are only part of your final grade See syllabus

537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Histograms

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Schedule for the semester

Wk Date Topic Wk Date Topic1 0822 Chaps 1 ndash 2 X 9 1017 Chap 102 0829 Chaps 3 ndash 4 X 10 1024 Chaps 10 ndash 113 0905 Chap 5 X 11 1031 Chaps 10 ndash 114 0912 Test ndash Chap 6 X 12 1107 Testndash Chap 145 0919 Chap 7 13 1114 Chap 146 0926 Chap 8 14 1128 Chap 187 1003 Chap 9 15 1205 Chap 188 1010 Test ndash Chap 10 16 1212 Exam

737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Programming assignment 003

File Based Address Book

Objectives are fairly straightforward

Accept commands from the user

Read strings from a data file

Search strings for data from user

Output strings to the screen in aparticular format or outputmessage

Submit your source code

This is a single person effort (not ateam effort)

Due by start of class 4 Oct 2016

837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Corrections and additions since last lecture

Graded and re-graded thetest

Check syllabus to see howgrades are computed

Homework for chapter 6 duebefore class

Exchanged e-mails and hadoffice hours (videoconference)

937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

This and that

Read from a file

Objectives are fairly straightforward

Read strings from a data file

First string is the key

Second string is the plain text

Output plain and ldquoencryptedrdquostrings to the screen in a particularorder

Submit your source code

This is a single person effort (not ateam effort)

Any questions or problems

1037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Flow of control

There are limited number of different ldquoflow of controlrdquo

Sequential ndash instructions are executed in order

Function calls ndash program execution is transferred to a functionand then returned (with or without a return value)

Selection ndash some instructions are executed but others are not

Looping ndash a set of instructions is executed more than once

1137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

The ldquoifrdquo statement

The ldquoifrdquo statement evaluates a conditional as ldquotruerdquo orldquofalserdquoWhen the conditional is ldquotruerdquo then the next statement isexecutedThe conditional can be simple or complex

Examples of ldquoifrdquo statementsif ( true ) cout ltlt The condition is true ltlt endl

if ( true )

cout ltlt The condition is true ltlt endl

if ( a gt 3 )

cout ltlt a is greater than 3 ltlt endl

if ( (a lt 2) || (3 lt a) )

cout ltlt a is less than 2 OR greater than 3 ltlt endl

if ( (a lt 2) ampamp (3 lt a) )

cout ltlt a is less than 2 AND greater than 3 (impossible) ltlt endl

1237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

What if we want to execute more than one statement

We look at what defines a statement

if ( true ) cout ltlt The condition is true ltlt endl

else cout ltlt The condition is false ltlt endl

if ( a gt 3 )

cout ltlt a is greater than 3 ltlt endl

cout ltlt And we can do other things ltlt endl

else

cout ltlt a is NOT greater than 3 ltlt endl

cout ltlt As well when the condition is false ltlt endl

1337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Basic looping structures

while loopwhile ( conditional) statements with changerfor loopfor (initial conditional changer) statements

do while loopdo statements with changer while (conditional)

Handcrafted (which we wonrsquot go into)

1437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

The ldquoinfiniterdquo loop

There may be times when you want a loop to repeat but theterminate conditions are too hard to make into a set ofcomparisonsstdstring fileName = tmptemptxt

stdifstream inputFile

int data = 0

inputFileopen(fileNamec_str())

for ( )

data ltlt inputFile

if (data == 37)

break

else

if ( data == 16)

continue

data += 42

break ldquobreaksrdquo out of the current control structure continue

ldquocontinuesrdquo execution at the top of the control structure

1537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

What if there is more than one ldquootherrdquo case

The ldquoifrdquo statement handles exactly one conditional and thenexecutes code based on whether that conditional is ldquotruerdquo orldquofalserdquoldquoifrdquo statements can be nested to create very complex conditionalexpressionsBut how can we efficiently handle many conditionals at onceEnter the ldquoswitchrdquo statement The ldquoswitchrdquo statementcompares one expression against a number of conditions andexecutes code when the condition is true Wersquoll play with the

ifcpp and switchcpp programs

1637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Notional ldquoswitchrdquo structure structure

The ldquoswitch statement is aselection control structure formulti-way branching

IntegralExpression ndash anyexpression that can bereduced to an integer value

case Constant ndash anyconstant value that is thesame type as theIntegralExpression

default ndash the ldquocaserdquo whenno other cases match

Image from [2]

1737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Same image

Image from [2]

1837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Example of a ldquoswitchrdquo statement

cin gtgt letter gtgt first gtgt second

switch (letter)

case rsquoArsquo

answer = (first + second)

cout ltlt first ltlt + ltlt second

ltlt is ltlt answer ltlt endl

break

case rsquoSrsquo

answer = (first - second)

cout ltlt first ltlt - ltlt second

ltlt is ltlt answer ltlt endl

break

1937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

More details about the switch statement

The value ofIntegralExpression (of charshort int long or enumtype) determines whichbranch is executed

Case labels are constantintegral expressions

Several case labels canprecede a statement

Control branches to thestatement following thecase label that matches the

value of IntegralExpression

Control proceeds throughall remaining statementsincluding the defaultunless redirected with break

If no case label matches thevalue of IntegralExpressioncontrol branches to thedefault label if present

Otherwise control passes tothe statement following theentire switch statement

Forgetting to use break can cause logical errors

2037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Misc things about break and continue statements

A break statement can beused in switch or any ofthe 3 looping structures

It causes an immediateexit from the currentstructure

If used in a nestedstructure it only exitsthe current structure

A continue statement canonly be used in a loopingstructure

It terminates the currentiteration but not theentire loopIn a ldquoforrdquo loop theupdate is still doneIn a ldquodo ndash whilerdquo theexit condition is tested

Indiscriminate use of break and continue can lead to confusingcode

2137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

C++ operators we will know and love

There are a lot of declaredoperators in C++ Over the nextfew months will will learn aboutthe ones in red and possibly theones in green

Image from [1]

2237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [1]

2337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Specialized C++ operators

What do these expressions do and why

Interesting expressions232 (alpha + beta)delta = 2 12

Confusing expressions

int1 = 14 int2 =++int1

int1 = 14 int2 =int1++

When in doubt fire up CodeBlocks and test them out

2837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

Bit operators

What do these fragments produce and why

When in doubt fire up CodeBlocks and test them out

2937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What if we donrsquot like the type of our variable

There may be some cases where we want the compiler to changethe ldquotyperdquo of our dataThis is known as ldquocastingrdquo the variable It really is changing thevalue of the variable to the desired type

Functional notationintVar = int(floatVar)

Prefix notationintVar = (int) floatVar

Keyword notationintVar = static castltintgt(floatVar)

Keyword notation is gaining popularity because it is easy to locatein multiple files

3037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What are the mechanics behind ldquocastingrdquo values

There are only two cases

If there is only one data type involved

Trivial case nothing happens

If there is more than one data type involved

Each data type is promoted to the next higher data typeuntil we have a trivial caseOrder of data type promotion int unsigned int long

float double long double

Casting also happens behind the scenes with conditionals Bestadvice is to compare like types

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Table of contents I

1 Test Results

2 Schedule

3 Miscellanea

4 Control Structs

5 Addrsquol Operrsquos

6 Break

7 Hands on

8 Q amp A

9 Conclusion

10 References

11 Files

337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Histograms

Histogram of questions and misses

437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Histograms

Histogram of letter grades

Test scores are only part of your final grade See syllabus

537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Histograms

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Schedule for the semester

Wk Date Topic Wk Date Topic1 0822 Chaps 1 ndash 2 X 9 1017 Chap 102 0829 Chaps 3 ndash 4 X 10 1024 Chaps 10 ndash 113 0905 Chap 5 X 11 1031 Chaps 10 ndash 114 0912 Test ndash Chap 6 X 12 1107 Testndash Chap 145 0919 Chap 7 13 1114 Chap 146 0926 Chap 8 14 1128 Chap 187 1003 Chap 9 15 1205 Chap 188 1010 Test ndash Chap 10 16 1212 Exam

737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Programming assignment 003

File Based Address Book

Objectives are fairly straightforward

Accept commands from the user

Read strings from a data file

Search strings for data from user

Output strings to the screen in aparticular format or outputmessage

Submit your source code

This is a single person effort (not ateam effort)

Due by start of class 4 Oct 2016

837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Corrections and additions since last lecture

Graded and re-graded thetest

Check syllabus to see howgrades are computed

Homework for chapter 6 duebefore class

Exchanged e-mails and hadoffice hours (videoconference)

937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

This and that

Read from a file

Objectives are fairly straightforward

Read strings from a data file

First string is the key

Second string is the plain text

Output plain and ldquoencryptedrdquostrings to the screen in a particularorder

Submit your source code

This is a single person effort (not ateam effort)

Any questions or problems

1037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Flow of control

There are limited number of different ldquoflow of controlrdquo

Sequential ndash instructions are executed in order

Function calls ndash program execution is transferred to a functionand then returned (with or without a return value)

Selection ndash some instructions are executed but others are not

Looping ndash a set of instructions is executed more than once

1137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

The ldquoifrdquo statement

The ldquoifrdquo statement evaluates a conditional as ldquotruerdquo orldquofalserdquoWhen the conditional is ldquotruerdquo then the next statement isexecutedThe conditional can be simple or complex

Examples of ldquoifrdquo statementsif ( true ) cout ltlt The condition is true ltlt endl

if ( true )

cout ltlt The condition is true ltlt endl

if ( a gt 3 )

cout ltlt a is greater than 3 ltlt endl

if ( (a lt 2) || (3 lt a) )

cout ltlt a is less than 2 OR greater than 3 ltlt endl

if ( (a lt 2) ampamp (3 lt a) )

cout ltlt a is less than 2 AND greater than 3 (impossible) ltlt endl

1237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

What if we want to execute more than one statement

We look at what defines a statement

if ( true ) cout ltlt The condition is true ltlt endl

else cout ltlt The condition is false ltlt endl

if ( a gt 3 )

cout ltlt a is greater than 3 ltlt endl

cout ltlt And we can do other things ltlt endl

else

cout ltlt a is NOT greater than 3 ltlt endl

cout ltlt As well when the condition is false ltlt endl

1337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Basic looping structures

while loopwhile ( conditional) statements with changerfor loopfor (initial conditional changer) statements

do while loopdo statements with changer while (conditional)

Handcrafted (which we wonrsquot go into)

1437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

The ldquoinfiniterdquo loop

There may be times when you want a loop to repeat but theterminate conditions are too hard to make into a set ofcomparisonsstdstring fileName = tmptemptxt

stdifstream inputFile

int data = 0

inputFileopen(fileNamec_str())

for ( )

data ltlt inputFile

if (data == 37)

break

else

if ( data == 16)

continue

data += 42

break ldquobreaksrdquo out of the current control structure continue

ldquocontinuesrdquo execution at the top of the control structure

1537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

What if there is more than one ldquootherrdquo case

The ldquoifrdquo statement handles exactly one conditional and thenexecutes code based on whether that conditional is ldquotruerdquo orldquofalserdquoldquoifrdquo statements can be nested to create very complex conditionalexpressionsBut how can we efficiently handle many conditionals at onceEnter the ldquoswitchrdquo statement The ldquoswitchrdquo statementcompares one expression against a number of conditions andexecutes code when the condition is true Wersquoll play with the

ifcpp and switchcpp programs

1637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Notional ldquoswitchrdquo structure structure

The ldquoswitch statement is aselection control structure formulti-way branching

IntegralExpression ndash anyexpression that can bereduced to an integer value

case Constant ndash anyconstant value that is thesame type as theIntegralExpression

default ndash the ldquocaserdquo whenno other cases match

Image from [2]

1737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Same image

Image from [2]

1837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Example of a ldquoswitchrdquo statement

cin gtgt letter gtgt first gtgt second

switch (letter)

case rsquoArsquo

answer = (first + second)

cout ltlt first ltlt + ltlt second

ltlt is ltlt answer ltlt endl

break

case rsquoSrsquo

answer = (first - second)

cout ltlt first ltlt - ltlt second

ltlt is ltlt answer ltlt endl

break

1937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

More details about the switch statement

The value ofIntegralExpression (of charshort int long or enumtype) determines whichbranch is executed

Case labels are constantintegral expressions

Several case labels canprecede a statement

Control branches to thestatement following thecase label that matches the

value of IntegralExpression

Control proceeds throughall remaining statementsincluding the defaultunless redirected with break

If no case label matches thevalue of IntegralExpressioncontrol branches to thedefault label if present

Otherwise control passes tothe statement following theentire switch statement

Forgetting to use break can cause logical errors

2037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Misc things about break and continue statements

A break statement can beused in switch or any ofthe 3 looping structures

It causes an immediateexit from the currentstructure

If used in a nestedstructure it only exitsthe current structure

A continue statement canonly be used in a loopingstructure

It terminates the currentiteration but not theentire loopIn a ldquoforrdquo loop theupdate is still doneIn a ldquodo ndash whilerdquo theexit condition is tested

Indiscriminate use of break and continue can lead to confusingcode

2137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

C++ operators we will know and love

There are a lot of declaredoperators in C++ Over the nextfew months will will learn aboutthe ones in red and possibly theones in green

Image from [1]

2237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [1]

2337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Specialized C++ operators

What do these expressions do and why

Interesting expressions232 (alpha + beta)delta = 2 12

Confusing expressions

int1 = 14 int2 =++int1

int1 = 14 int2 =int1++

When in doubt fire up CodeBlocks and test them out

2837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

Bit operators

What do these fragments produce and why

When in doubt fire up CodeBlocks and test them out

2937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What if we donrsquot like the type of our variable

There may be some cases where we want the compiler to changethe ldquotyperdquo of our dataThis is known as ldquocastingrdquo the variable It really is changing thevalue of the variable to the desired type

Functional notationintVar = int(floatVar)

Prefix notationintVar = (int) floatVar

Keyword notationintVar = static castltintgt(floatVar)

Keyword notation is gaining popularity because it is easy to locatein multiple files

3037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What are the mechanics behind ldquocastingrdquo values

There are only two cases

If there is only one data type involved

Trivial case nothing happens

If there is more than one data type involved

Each data type is promoted to the next higher data typeuntil we have a trivial caseOrder of data type promotion int unsigned int long

float double long double

Casting also happens behind the scenes with conditionals Bestadvice is to compare like types

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Histograms

Histogram of questions and misses

437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Histograms

Histogram of letter grades

Test scores are only part of your final grade See syllabus

537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Histograms

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Schedule for the semester

Wk Date Topic Wk Date Topic1 0822 Chaps 1 ndash 2 X 9 1017 Chap 102 0829 Chaps 3 ndash 4 X 10 1024 Chaps 10 ndash 113 0905 Chap 5 X 11 1031 Chaps 10 ndash 114 0912 Test ndash Chap 6 X 12 1107 Testndash Chap 145 0919 Chap 7 13 1114 Chap 146 0926 Chap 8 14 1128 Chap 187 1003 Chap 9 15 1205 Chap 188 1010 Test ndash Chap 10 16 1212 Exam

737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Programming assignment 003

File Based Address Book

Objectives are fairly straightforward

Accept commands from the user

Read strings from a data file

Search strings for data from user

Output strings to the screen in aparticular format or outputmessage

Submit your source code

This is a single person effort (not ateam effort)

Due by start of class 4 Oct 2016

837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Corrections and additions since last lecture

Graded and re-graded thetest

Check syllabus to see howgrades are computed

Homework for chapter 6 duebefore class

Exchanged e-mails and hadoffice hours (videoconference)

937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

This and that

Read from a file

Objectives are fairly straightforward

Read strings from a data file

First string is the key

Second string is the plain text

Output plain and ldquoencryptedrdquostrings to the screen in a particularorder

Submit your source code

This is a single person effort (not ateam effort)

Any questions or problems

1037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Flow of control

There are limited number of different ldquoflow of controlrdquo

Sequential ndash instructions are executed in order

Function calls ndash program execution is transferred to a functionand then returned (with or without a return value)

Selection ndash some instructions are executed but others are not

Looping ndash a set of instructions is executed more than once

1137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

The ldquoifrdquo statement

The ldquoifrdquo statement evaluates a conditional as ldquotruerdquo orldquofalserdquoWhen the conditional is ldquotruerdquo then the next statement isexecutedThe conditional can be simple or complex

Examples of ldquoifrdquo statementsif ( true ) cout ltlt The condition is true ltlt endl

if ( true )

cout ltlt The condition is true ltlt endl

if ( a gt 3 )

cout ltlt a is greater than 3 ltlt endl

if ( (a lt 2) || (3 lt a) )

cout ltlt a is less than 2 OR greater than 3 ltlt endl

if ( (a lt 2) ampamp (3 lt a) )

cout ltlt a is less than 2 AND greater than 3 (impossible) ltlt endl

1237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

What if we want to execute more than one statement

We look at what defines a statement

if ( true ) cout ltlt The condition is true ltlt endl

else cout ltlt The condition is false ltlt endl

if ( a gt 3 )

cout ltlt a is greater than 3 ltlt endl

cout ltlt And we can do other things ltlt endl

else

cout ltlt a is NOT greater than 3 ltlt endl

cout ltlt As well when the condition is false ltlt endl

1337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Basic looping structures

while loopwhile ( conditional) statements with changerfor loopfor (initial conditional changer) statements

do while loopdo statements with changer while (conditional)

Handcrafted (which we wonrsquot go into)

1437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

The ldquoinfiniterdquo loop

There may be times when you want a loop to repeat but theterminate conditions are too hard to make into a set ofcomparisonsstdstring fileName = tmptemptxt

stdifstream inputFile

int data = 0

inputFileopen(fileNamec_str())

for ( )

data ltlt inputFile

if (data == 37)

break

else

if ( data == 16)

continue

data += 42

break ldquobreaksrdquo out of the current control structure continue

ldquocontinuesrdquo execution at the top of the control structure

1537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

What if there is more than one ldquootherrdquo case

The ldquoifrdquo statement handles exactly one conditional and thenexecutes code based on whether that conditional is ldquotruerdquo orldquofalserdquoldquoifrdquo statements can be nested to create very complex conditionalexpressionsBut how can we efficiently handle many conditionals at onceEnter the ldquoswitchrdquo statement The ldquoswitchrdquo statementcompares one expression against a number of conditions andexecutes code when the condition is true Wersquoll play with the

ifcpp and switchcpp programs

1637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Notional ldquoswitchrdquo structure structure

The ldquoswitch statement is aselection control structure formulti-way branching

IntegralExpression ndash anyexpression that can bereduced to an integer value

case Constant ndash anyconstant value that is thesame type as theIntegralExpression

default ndash the ldquocaserdquo whenno other cases match

Image from [2]

1737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Same image

Image from [2]

1837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Example of a ldquoswitchrdquo statement

cin gtgt letter gtgt first gtgt second

switch (letter)

case rsquoArsquo

answer = (first + second)

cout ltlt first ltlt + ltlt second

ltlt is ltlt answer ltlt endl

break

case rsquoSrsquo

answer = (first - second)

cout ltlt first ltlt - ltlt second

ltlt is ltlt answer ltlt endl

break

1937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

More details about the switch statement

The value ofIntegralExpression (of charshort int long or enumtype) determines whichbranch is executed

Case labels are constantintegral expressions

Several case labels canprecede a statement

Control branches to thestatement following thecase label that matches the

value of IntegralExpression

Control proceeds throughall remaining statementsincluding the defaultunless redirected with break

If no case label matches thevalue of IntegralExpressioncontrol branches to thedefault label if present

Otherwise control passes tothe statement following theentire switch statement

Forgetting to use break can cause logical errors

2037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Misc things about break and continue statements

A break statement can beused in switch or any ofthe 3 looping structures

It causes an immediateexit from the currentstructure

If used in a nestedstructure it only exitsthe current structure

A continue statement canonly be used in a loopingstructure

It terminates the currentiteration but not theentire loopIn a ldquoforrdquo loop theupdate is still doneIn a ldquodo ndash whilerdquo theexit condition is tested

Indiscriminate use of break and continue can lead to confusingcode

2137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

C++ operators we will know and love

There are a lot of declaredoperators in C++ Over the nextfew months will will learn aboutthe ones in red and possibly theones in green

Image from [1]

2237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [1]

2337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Specialized C++ operators

What do these expressions do and why

Interesting expressions232 (alpha + beta)delta = 2 12

Confusing expressions

int1 = 14 int2 =++int1

int1 = 14 int2 =int1++

When in doubt fire up CodeBlocks and test them out

2837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

Bit operators

What do these fragments produce and why

When in doubt fire up CodeBlocks and test them out

2937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What if we donrsquot like the type of our variable

There may be some cases where we want the compiler to changethe ldquotyperdquo of our dataThis is known as ldquocastingrdquo the variable It really is changing thevalue of the variable to the desired type

Functional notationintVar = int(floatVar)

Prefix notationintVar = (int) floatVar

Keyword notationintVar = static castltintgt(floatVar)

Keyword notation is gaining popularity because it is easy to locatein multiple files

3037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What are the mechanics behind ldquocastingrdquo values

There are only two cases

If there is only one data type involved

Trivial case nothing happens

If there is more than one data type involved

Each data type is promoted to the next higher data typeuntil we have a trivial caseOrder of data type promotion int unsigned int long

float double long double

Casting also happens behind the scenes with conditionals Bestadvice is to compare like types

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Histograms

Histogram of letter grades

Test scores are only part of your final grade See syllabus

537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Histograms

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Schedule for the semester

Wk Date Topic Wk Date Topic1 0822 Chaps 1 ndash 2 X 9 1017 Chap 102 0829 Chaps 3 ndash 4 X 10 1024 Chaps 10 ndash 113 0905 Chap 5 X 11 1031 Chaps 10 ndash 114 0912 Test ndash Chap 6 X 12 1107 Testndash Chap 145 0919 Chap 7 13 1114 Chap 146 0926 Chap 8 14 1128 Chap 187 1003 Chap 9 15 1205 Chap 188 1010 Test ndash Chap 10 16 1212 Exam

737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Programming assignment 003

File Based Address Book

Objectives are fairly straightforward

Accept commands from the user

Read strings from a data file

Search strings for data from user

Output strings to the screen in aparticular format or outputmessage

Submit your source code

This is a single person effort (not ateam effort)

Due by start of class 4 Oct 2016

837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Corrections and additions since last lecture

Graded and re-graded thetest

Check syllabus to see howgrades are computed

Homework for chapter 6 duebefore class

Exchanged e-mails and hadoffice hours (videoconference)

937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

This and that

Read from a file

Objectives are fairly straightforward

Read strings from a data file

First string is the key

Second string is the plain text

Output plain and ldquoencryptedrdquostrings to the screen in a particularorder

Submit your source code

This is a single person effort (not ateam effort)

Any questions or problems

1037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Flow of control

There are limited number of different ldquoflow of controlrdquo

Sequential ndash instructions are executed in order

Function calls ndash program execution is transferred to a functionand then returned (with or without a return value)

Selection ndash some instructions are executed but others are not

Looping ndash a set of instructions is executed more than once

1137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

The ldquoifrdquo statement

The ldquoifrdquo statement evaluates a conditional as ldquotruerdquo orldquofalserdquoWhen the conditional is ldquotruerdquo then the next statement isexecutedThe conditional can be simple or complex

Examples of ldquoifrdquo statementsif ( true ) cout ltlt The condition is true ltlt endl

if ( true )

cout ltlt The condition is true ltlt endl

if ( a gt 3 )

cout ltlt a is greater than 3 ltlt endl

if ( (a lt 2) || (3 lt a) )

cout ltlt a is less than 2 OR greater than 3 ltlt endl

if ( (a lt 2) ampamp (3 lt a) )

cout ltlt a is less than 2 AND greater than 3 (impossible) ltlt endl

1237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

What if we want to execute more than one statement

We look at what defines a statement

if ( true ) cout ltlt The condition is true ltlt endl

else cout ltlt The condition is false ltlt endl

if ( a gt 3 )

cout ltlt a is greater than 3 ltlt endl

cout ltlt And we can do other things ltlt endl

else

cout ltlt a is NOT greater than 3 ltlt endl

cout ltlt As well when the condition is false ltlt endl

1337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Basic looping structures

while loopwhile ( conditional) statements with changerfor loopfor (initial conditional changer) statements

do while loopdo statements with changer while (conditional)

Handcrafted (which we wonrsquot go into)

1437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

The ldquoinfiniterdquo loop

There may be times when you want a loop to repeat but theterminate conditions are too hard to make into a set ofcomparisonsstdstring fileName = tmptemptxt

stdifstream inputFile

int data = 0

inputFileopen(fileNamec_str())

for ( )

data ltlt inputFile

if (data == 37)

break

else

if ( data == 16)

continue

data += 42

break ldquobreaksrdquo out of the current control structure continue

ldquocontinuesrdquo execution at the top of the control structure

1537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

What if there is more than one ldquootherrdquo case

The ldquoifrdquo statement handles exactly one conditional and thenexecutes code based on whether that conditional is ldquotruerdquo orldquofalserdquoldquoifrdquo statements can be nested to create very complex conditionalexpressionsBut how can we efficiently handle many conditionals at onceEnter the ldquoswitchrdquo statement The ldquoswitchrdquo statementcompares one expression against a number of conditions andexecutes code when the condition is true Wersquoll play with the

ifcpp and switchcpp programs

1637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Notional ldquoswitchrdquo structure structure

The ldquoswitch statement is aselection control structure formulti-way branching

IntegralExpression ndash anyexpression that can bereduced to an integer value

case Constant ndash anyconstant value that is thesame type as theIntegralExpression

default ndash the ldquocaserdquo whenno other cases match

Image from [2]

1737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Same image

Image from [2]

1837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Example of a ldquoswitchrdquo statement

cin gtgt letter gtgt first gtgt second

switch (letter)

case rsquoArsquo

answer = (first + second)

cout ltlt first ltlt + ltlt second

ltlt is ltlt answer ltlt endl

break

case rsquoSrsquo

answer = (first - second)

cout ltlt first ltlt - ltlt second

ltlt is ltlt answer ltlt endl

break

1937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

More details about the switch statement

The value ofIntegralExpression (of charshort int long or enumtype) determines whichbranch is executed

Case labels are constantintegral expressions

Several case labels canprecede a statement

Control branches to thestatement following thecase label that matches the

value of IntegralExpression

Control proceeds throughall remaining statementsincluding the defaultunless redirected with break

If no case label matches thevalue of IntegralExpressioncontrol branches to thedefault label if present

Otherwise control passes tothe statement following theentire switch statement

Forgetting to use break can cause logical errors

2037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Misc things about break and continue statements

A break statement can beused in switch or any ofthe 3 looping structures

It causes an immediateexit from the currentstructure

If used in a nestedstructure it only exitsthe current structure

A continue statement canonly be used in a loopingstructure

It terminates the currentiteration but not theentire loopIn a ldquoforrdquo loop theupdate is still doneIn a ldquodo ndash whilerdquo theexit condition is tested

Indiscriminate use of break and continue can lead to confusingcode

2137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

C++ operators we will know and love

There are a lot of declaredoperators in C++ Over the nextfew months will will learn aboutthe ones in red and possibly theones in green

Image from [1]

2237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [1]

2337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Specialized C++ operators

What do these expressions do and why

Interesting expressions232 (alpha + beta)delta = 2 12

Confusing expressions

int1 = 14 int2 =++int1

int1 = 14 int2 =int1++

When in doubt fire up CodeBlocks and test them out

2837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

Bit operators

What do these fragments produce and why

When in doubt fire up CodeBlocks and test them out

2937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What if we donrsquot like the type of our variable

There may be some cases where we want the compiler to changethe ldquotyperdquo of our dataThis is known as ldquocastingrdquo the variable It really is changing thevalue of the variable to the desired type

Functional notationintVar = int(floatVar)

Prefix notationintVar = (int) floatVar

Keyword notationintVar = static castltintgt(floatVar)

Keyword notation is gaining popularity because it is easy to locatein multiple files

3037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What are the mechanics behind ldquocastingrdquo values

There are only two cases

If there is only one data type involved

Trivial case nothing happens

If there is more than one data type involved

Each data type is promoted to the next higher data typeuntil we have a trivial caseOrder of data type promotion int unsigned int long

float double long double

Casting also happens behind the scenes with conditionals Bestadvice is to compare like types

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Histograms

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Schedule for the semester

Wk Date Topic Wk Date Topic1 0822 Chaps 1 ndash 2 X 9 1017 Chap 102 0829 Chaps 3 ndash 4 X 10 1024 Chaps 10 ndash 113 0905 Chap 5 X 11 1031 Chaps 10 ndash 114 0912 Test ndash Chap 6 X 12 1107 Testndash Chap 145 0919 Chap 7 13 1114 Chap 146 0926 Chap 8 14 1128 Chap 187 1003 Chap 9 15 1205 Chap 188 1010 Test ndash Chap 10 16 1212 Exam

737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Programming assignment 003

File Based Address Book

Objectives are fairly straightforward

Accept commands from the user

Read strings from a data file

Search strings for data from user

Output strings to the screen in aparticular format or outputmessage

Submit your source code

This is a single person effort (not ateam effort)

Due by start of class 4 Oct 2016

837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Corrections and additions since last lecture

Graded and re-graded thetest

Check syllabus to see howgrades are computed

Homework for chapter 6 duebefore class

Exchanged e-mails and hadoffice hours (videoconference)

937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

This and that

Read from a file

Objectives are fairly straightforward

Read strings from a data file

First string is the key

Second string is the plain text

Output plain and ldquoencryptedrdquostrings to the screen in a particularorder

Submit your source code

This is a single person effort (not ateam effort)

Any questions or problems

1037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Flow of control

There are limited number of different ldquoflow of controlrdquo

Sequential ndash instructions are executed in order

Function calls ndash program execution is transferred to a functionand then returned (with or without a return value)

Selection ndash some instructions are executed but others are not

Looping ndash a set of instructions is executed more than once

1137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

The ldquoifrdquo statement

The ldquoifrdquo statement evaluates a conditional as ldquotruerdquo orldquofalserdquoWhen the conditional is ldquotruerdquo then the next statement isexecutedThe conditional can be simple or complex

Examples of ldquoifrdquo statementsif ( true ) cout ltlt The condition is true ltlt endl

if ( true )

cout ltlt The condition is true ltlt endl

if ( a gt 3 )

cout ltlt a is greater than 3 ltlt endl

if ( (a lt 2) || (3 lt a) )

cout ltlt a is less than 2 OR greater than 3 ltlt endl

if ( (a lt 2) ampamp (3 lt a) )

cout ltlt a is less than 2 AND greater than 3 (impossible) ltlt endl

1237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

What if we want to execute more than one statement

We look at what defines a statement

if ( true ) cout ltlt The condition is true ltlt endl

else cout ltlt The condition is false ltlt endl

if ( a gt 3 )

cout ltlt a is greater than 3 ltlt endl

cout ltlt And we can do other things ltlt endl

else

cout ltlt a is NOT greater than 3 ltlt endl

cout ltlt As well when the condition is false ltlt endl

1337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Basic looping structures

while loopwhile ( conditional) statements with changerfor loopfor (initial conditional changer) statements

do while loopdo statements with changer while (conditional)

Handcrafted (which we wonrsquot go into)

1437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

The ldquoinfiniterdquo loop

There may be times when you want a loop to repeat but theterminate conditions are too hard to make into a set ofcomparisonsstdstring fileName = tmptemptxt

stdifstream inputFile

int data = 0

inputFileopen(fileNamec_str())

for ( )

data ltlt inputFile

if (data == 37)

break

else

if ( data == 16)

continue

data += 42

break ldquobreaksrdquo out of the current control structure continue

ldquocontinuesrdquo execution at the top of the control structure

1537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

What if there is more than one ldquootherrdquo case

The ldquoifrdquo statement handles exactly one conditional and thenexecutes code based on whether that conditional is ldquotruerdquo orldquofalserdquoldquoifrdquo statements can be nested to create very complex conditionalexpressionsBut how can we efficiently handle many conditionals at onceEnter the ldquoswitchrdquo statement The ldquoswitchrdquo statementcompares one expression against a number of conditions andexecutes code when the condition is true Wersquoll play with the

ifcpp and switchcpp programs

1637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Notional ldquoswitchrdquo structure structure

The ldquoswitch statement is aselection control structure formulti-way branching

IntegralExpression ndash anyexpression that can bereduced to an integer value

case Constant ndash anyconstant value that is thesame type as theIntegralExpression

default ndash the ldquocaserdquo whenno other cases match

Image from [2]

1737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Same image

Image from [2]

1837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Example of a ldquoswitchrdquo statement

cin gtgt letter gtgt first gtgt second

switch (letter)

case rsquoArsquo

answer = (first + second)

cout ltlt first ltlt + ltlt second

ltlt is ltlt answer ltlt endl

break

case rsquoSrsquo

answer = (first - second)

cout ltlt first ltlt - ltlt second

ltlt is ltlt answer ltlt endl

break

1937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

More details about the switch statement

The value ofIntegralExpression (of charshort int long or enumtype) determines whichbranch is executed

Case labels are constantintegral expressions

Several case labels canprecede a statement

Control branches to thestatement following thecase label that matches the

value of IntegralExpression

Control proceeds throughall remaining statementsincluding the defaultunless redirected with break

If no case label matches thevalue of IntegralExpressioncontrol branches to thedefault label if present

Otherwise control passes tothe statement following theentire switch statement

Forgetting to use break can cause logical errors

2037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Misc things about break and continue statements

A break statement can beused in switch or any ofthe 3 looping structures

It causes an immediateexit from the currentstructure

If used in a nestedstructure it only exitsthe current structure

A continue statement canonly be used in a loopingstructure

It terminates the currentiteration but not theentire loopIn a ldquoforrdquo loop theupdate is still doneIn a ldquodo ndash whilerdquo theexit condition is tested

Indiscriminate use of break and continue can lead to confusingcode

2137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

C++ operators we will know and love

There are a lot of declaredoperators in C++ Over the nextfew months will will learn aboutthe ones in red and possibly theones in green

Image from [1]

2237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [1]

2337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Specialized C++ operators

What do these expressions do and why

Interesting expressions232 (alpha + beta)delta = 2 12

Confusing expressions

int1 = 14 int2 =++int1

int1 = 14 int2 =int1++

When in doubt fire up CodeBlocks and test them out

2837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

Bit operators

What do these fragments produce and why

When in doubt fire up CodeBlocks and test them out

2937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What if we donrsquot like the type of our variable

There may be some cases where we want the compiler to changethe ldquotyperdquo of our dataThis is known as ldquocastingrdquo the variable It really is changing thevalue of the variable to the desired type

Functional notationintVar = int(floatVar)

Prefix notationintVar = (int) floatVar

Keyword notationintVar = static castltintgt(floatVar)

Keyword notation is gaining popularity because it is easy to locatein multiple files

3037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What are the mechanics behind ldquocastingrdquo values

There are only two cases

If there is only one data type involved

Trivial case nothing happens

If there is more than one data type involved

Each data type is promoted to the next higher data typeuntil we have a trivial caseOrder of data type promotion int unsigned int long

float double long double

Casting also happens behind the scenes with conditionals Bestadvice is to compare like types

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Schedule for the semester

Wk Date Topic Wk Date Topic1 0822 Chaps 1 ndash 2 X 9 1017 Chap 102 0829 Chaps 3 ndash 4 X 10 1024 Chaps 10 ndash 113 0905 Chap 5 X 11 1031 Chaps 10 ndash 114 0912 Test ndash Chap 6 X 12 1107 Testndash Chap 145 0919 Chap 7 13 1114 Chap 146 0926 Chap 8 14 1128 Chap 187 1003 Chap 9 15 1205 Chap 188 1010 Test ndash Chap 10 16 1212 Exam

737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Programming assignment 003

File Based Address Book

Objectives are fairly straightforward

Accept commands from the user

Read strings from a data file

Search strings for data from user

Output strings to the screen in aparticular format or outputmessage

Submit your source code

This is a single person effort (not ateam effort)

Due by start of class 4 Oct 2016

837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Corrections and additions since last lecture

Graded and re-graded thetest

Check syllabus to see howgrades are computed

Homework for chapter 6 duebefore class

Exchanged e-mails and hadoffice hours (videoconference)

937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

This and that

Read from a file

Objectives are fairly straightforward

Read strings from a data file

First string is the key

Second string is the plain text

Output plain and ldquoencryptedrdquostrings to the screen in a particularorder

Submit your source code

This is a single person effort (not ateam effort)

Any questions or problems

1037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Flow of control

There are limited number of different ldquoflow of controlrdquo

Sequential ndash instructions are executed in order

Function calls ndash program execution is transferred to a functionand then returned (with or without a return value)

Selection ndash some instructions are executed but others are not

Looping ndash a set of instructions is executed more than once

1137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

The ldquoifrdquo statement

The ldquoifrdquo statement evaluates a conditional as ldquotruerdquo orldquofalserdquoWhen the conditional is ldquotruerdquo then the next statement isexecutedThe conditional can be simple or complex

Examples of ldquoifrdquo statementsif ( true ) cout ltlt The condition is true ltlt endl

if ( true )

cout ltlt The condition is true ltlt endl

if ( a gt 3 )

cout ltlt a is greater than 3 ltlt endl

if ( (a lt 2) || (3 lt a) )

cout ltlt a is less than 2 OR greater than 3 ltlt endl

if ( (a lt 2) ampamp (3 lt a) )

cout ltlt a is less than 2 AND greater than 3 (impossible) ltlt endl

1237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

What if we want to execute more than one statement

We look at what defines a statement

if ( true ) cout ltlt The condition is true ltlt endl

else cout ltlt The condition is false ltlt endl

if ( a gt 3 )

cout ltlt a is greater than 3 ltlt endl

cout ltlt And we can do other things ltlt endl

else

cout ltlt a is NOT greater than 3 ltlt endl

cout ltlt As well when the condition is false ltlt endl

1337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Basic looping structures

while loopwhile ( conditional) statements with changerfor loopfor (initial conditional changer) statements

do while loopdo statements with changer while (conditional)

Handcrafted (which we wonrsquot go into)

1437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

The ldquoinfiniterdquo loop

There may be times when you want a loop to repeat but theterminate conditions are too hard to make into a set ofcomparisonsstdstring fileName = tmptemptxt

stdifstream inputFile

int data = 0

inputFileopen(fileNamec_str())

for ( )

data ltlt inputFile

if (data == 37)

break

else

if ( data == 16)

continue

data += 42

break ldquobreaksrdquo out of the current control structure continue

ldquocontinuesrdquo execution at the top of the control structure

1537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

What if there is more than one ldquootherrdquo case

The ldquoifrdquo statement handles exactly one conditional and thenexecutes code based on whether that conditional is ldquotruerdquo orldquofalserdquoldquoifrdquo statements can be nested to create very complex conditionalexpressionsBut how can we efficiently handle many conditionals at onceEnter the ldquoswitchrdquo statement The ldquoswitchrdquo statementcompares one expression against a number of conditions andexecutes code when the condition is true Wersquoll play with the

ifcpp and switchcpp programs

1637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Notional ldquoswitchrdquo structure structure

The ldquoswitch statement is aselection control structure formulti-way branching

IntegralExpression ndash anyexpression that can bereduced to an integer value

case Constant ndash anyconstant value that is thesame type as theIntegralExpression

default ndash the ldquocaserdquo whenno other cases match

Image from [2]

1737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Same image

Image from [2]

1837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Example of a ldquoswitchrdquo statement

cin gtgt letter gtgt first gtgt second

switch (letter)

case rsquoArsquo

answer = (first + second)

cout ltlt first ltlt + ltlt second

ltlt is ltlt answer ltlt endl

break

case rsquoSrsquo

answer = (first - second)

cout ltlt first ltlt - ltlt second

ltlt is ltlt answer ltlt endl

break

1937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

More details about the switch statement

The value ofIntegralExpression (of charshort int long or enumtype) determines whichbranch is executed

Case labels are constantintegral expressions

Several case labels canprecede a statement

Control branches to thestatement following thecase label that matches the

value of IntegralExpression

Control proceeds throughall remaining statementsincluding the defaultunless redirected with break

If no case label matches thevalue of IntegralExpressioncontrol branches to thedefault label if present

Otherwise control passes tothe statement following theentire switch statement

Forgetting to use break can cause logical errors

2037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Misc things about break and continue statements

A break statement can beused in switch or any ofthe 3 looping structures

It causes an immediateexit from the currentstructure

If used in a nestedstructure it only exitsthe current structure

A continue statement canonly be used in a loopingstructure

It terminates the currentiteration but not theentire loopIn a ldquoforrdquo loop theupdate is still doneIn a ldquodo ndash whilerdquo theexit condition is tested

Indiscriminate use of break and continue can lead to confusingcode

2137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

C++ operators we will know and love

There are a lot of declaredoperators in C++ Over the nextfew months will will learn aboutthe ones in red and possibly theones in green

Image from [1]

2237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [1]

2337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Specialized C++ operators

What do these expressions do and why

Interesting expressions232 (alpha + beta)delta = 2 12

Confusing expressions

int1 = 14 int2 =++int1

int1 = 14 int2 =int1++

When in doubt fire up CodeBlocks and test them out

2837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

Bit operators

What do these fragments produce and why

When in doubt fire up CodeBlocks and test them out

2937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What if we donrsquot like the type of our variable

There may be some cases where we want the compiler to changethe ldquotyperdquo of our dataThis is known as ldquocastingrdquo the variable It really is changing thevalue of the variable to the desired type

Functional notationintVar = int(floatVar)

Prefix notationintVar = (int) floatVar

Keyword notationintVar = static castltintgt(floatVar)

Keyword notation is gaining popularity because it is easy to locatein multiple files

3037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What are the mechanics behind ldquocastingrdquo values

There are only two cases

If there is only one data type involved

Trivial case nothing happens

If there is more than one data type involved

Each data type is promoted to the next higher data typeuntil we have a trivial caseOrder of data type promotion int unsigned int long

float double long double

Casting also happens behind the scenes with conditionals Bestadvice is to compare like types

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Programming assignment 003

File Based Address Book

Objectives are fairly straightforward

Accept commands from the user

Read strings from a data file

Search strings for data from user

Output strings to the screen in aparticular format or outputmessage

Submit your source code

This is a single person effort (not ateam effort)

Due by start of class 4 Oct 2016

837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Corrections and additions since last lecture

Graded and re-graded thetest

Check syllabus to see howgrades are computed

Homework for chapter 6 duebefore class

Exchanged e-mails and hadoffice hours (videoconference)

937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

This and that

Read from a file

Objectives are fairly straightforward

Read strings from a data file

First string is the key

Second string is the plain text

Output plain and ldquoencryptedrdquostrings to the screen in a particularorder

Submit your source code

This is a single person effort (not ateam effort)

Any questions or problems

1037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Flow of control

There are limited number of different ldquoflow of controlrdquo

Sequential ndash instructions are executed in order

Function calls ndash program execution is transferred to a functionand then returned (with or without a return value)

Selection ndash some instructions are executed but others are not

Looping ndash a set of instructions is executed more than once

1137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

The ldquoifrdquo statement

The ldquoifrdquo statement evaluates a conditional as ldquotruerdquo orldquofalserdquoWhen the conditional is ldquotruerdquo then the next statement isexecutedThe conditional can be simple or complex

Examples of ldquoifrdquo statementsif ( true ) cout ltlt The condition is true ltlt endl

if ( true )

cout ltlt The condition is true ltlt endl

if ( a gt 3 )

cout ltlt a is greater than 3 ltlt endl

if ( (a lt 2) || (3 lt a) )

cout ltlt a is less than 2 OR greater than 3 ltlt endl

if ( (a lt 2) ampamp (3 lt a) )

cout ltlt a is less than 2 AND greater than 3 (impossible) ltlt endl

1237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

What if we want to execute more than one statement

We look at what defines a statement

if ( true ) cout ltlt The condition is true ltlt endl

else cout ltlt The condition is false ltlt endl

if ( a gt 3 )

cout ltlt a is greater than 3 ltlt endl

cout ltlt And we can do other things ltlt endl

else

cout ltlt a is NOT greater than 3 ltlt endl

cout ltlt As well when the condition is false ltlt endl

1337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Basic looping structures

while loopwhile ( conditional) statements with changerfor loopfor (initial conditional changer) statements

do while loopdo statements with changer while (conditional)

Handcrafted (which we wonrsquot go into)

1437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

The ldquoinfiniterdquo loop

There may be times when you want a loop to repeat but theterminate conditions are too hard to make into a set ofcomparisonsstdstring fileName = tmptemptxt

stdifstream inputFile

int data = 0

inputFileopen(fileNamec_str())

for ( )

data ltlt inputFile

if (data == 37)

break

else

if ( data == 16)

continue

data += 42

break ldquobreaksrdquo out of the current control structure continue

ldquocontinuesrdquo execution at the top of the control structure

1537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

What if there is more than one ldquootherrdquo case

The ldquoifrdquo statement handles exactly one conditional and thenexecutes code based on whether that conditional is ldquotruerdquo orldquofalserdquoldquoifrdquo statements can be nested to create very complex conditionalexpressionsBut how can we efficiently handle many conditionals at onceEnter the ldquoswitchrdquo statement The ldquoswitchrdquo statementcompares one expression against a number of conditions andexecutes code when the condition is true Wersquoll play with the

ifcpp and switchcpp programs

1637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Notional ldquoswitchrdquo structure structure

The ldquoswitch statement is aselection control structure formulti-way branching

IntegralExpression ndash anyexpression that can bereduced to an integer value

case Constant ndash anyconstant value that is thesame type as theIntegralExpression

default ndash the ldquocaserdquo whenno other cases match

Image from [2]

1737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Same image

Image from [2]

1837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Example of a ldquoswitchrdquo statement

cin gtgt letter gtgt first gtgt second

switch (letter)

case rsquoArsquo

answer = (first + second)

cout ltlt first ltlt + ltlt second

ltlt is ltlt answer ltlt endl

break

case rsquoSrsquo

answer = (first - second)

cout ltlt first ltlt - ltlt second

ltlt is ltlt answer ltlt endl

break

1937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

More details about the switch statement

The value ofIntegralExpression (of charshort int long or enumtype) determines whichbranch is executed

Case labels are constantintegral expressions

Several case labels canprecede a statement

Control branches to thestatement following thecase label that matches the

value of IntegralExpression

Control proceeds throughall remaining statementsincluding the defaultunless redirected with break

If no case label matches thevalue of IntegralExpressioncontrol branches to thedefault label if present

Otherwise control passes tothe statement following theentire switch statement

Forgetting to use break can cause logical errors

2037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Misc things about break and continue statements

A break statement can beused in switch or any ofthe 3 looping structures

It causes an immediateexit from the currentstructure

If used in a nestedstructure it only exitsthe current structure

A continue statement canonly be used in a loopingstructure

It terminates the currentiteration but not theentire loopIn a ldquoforrdquo loop theupdate is still doneIn a ldquodo ndash whilerdquo theexit condition is tested

Indiscriminate use of break and continue can lead to confusingcode

2137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

C++ operators we will know and love

There are a lot of declaredoperators in C++ Over the nextfew months will will learn aboutthe ones in red and possibly theones in green

Image from [1]

2237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [1]

2337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Specialized C++ operators

What do these expressions do and why

Interesting expressions232 (alpha + beta)delta = 2 12

Confusing expressions

int1 = 14 int2 =++int1

int1 = 14 int2 =int1++

When in doubt fire up CodeBlocks and test them out

2837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

Bit operators

What do these fragments produce and why

When in doubt fire up CodeBlocks and test them out

2937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What if we donrsquot like the type of our variable

There may be some cases where we want the compiler to changethe ldquotyperdquo of our dataThis is known as ldquocastingrdquo the variable It really is changing thevalue of the variable to the desired type

Functional notationintVar = int(floatVar)

Prefix notationintVar = (int) floatVar

Keyword notationintVar = static castltintgt(floatVar)

Keyword notation is gaining popularity because it is easy to locatein multiple files

3037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What are the mechanics behind ldquocastingrdquo values

There are only two cases

If there is only one data type involved

Trivial case nothing happens

If there is more than one data type involved

Each data type is promoted to the next higher data typeuntil we have a trivial caseOrder of data type promotion int unsigned int long

float double long double

Casting also happens behind the scenes with conditionals Bestadvice is to compare like types

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Corrections and additions since last lecture

Graded and re-graded thetest

Check syllabus to see howgrades are computed

Homework for chapter 6 duebefore class

Exchanged e-mails and hadoffice hours (videoconference)

937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

This and that

Read from a file

Objectives are fairly straightforward

Read strings from a data file

First string is the key

Second string is the plain text

Output plain and ldquoencryptedrdquostrings to the screen in a particularorder

Submit your source code

This is a single person effort (not ateam effort)

Any questions or problems

1037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Flow of control

There are limited number of different ldquoflow of controlrdquo

Sequential ndash instructions are executed in order

Function calls ndash program execution is transferred to a functionand then returned (with or without a return value)

Selection ndash some instructions are executed but others are not

Looping ndash a set of instructions is executed more than once

1137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

The ldquoifrdquo statement

The ldquoifrdquo statement evaluates a conditional as ldquotruerdquo orldquofalserdquoWhen the conditional is ldquotruerdquo then the next statement isexecutedThe conditional can be simple or complex

Examples of ldquoifrdquo statementsif ( true ) cout ltlt The condition is true ltlt endl

if ( true )

cout ltlt The condition is true ltlt endl

if ( a gt 3 )

cout ltlt a is greater than 3 ltlt endl

if ( (a lt 2) || (3 lt a) )

cout ltlt a is less than 2 OR greater than 3 ltlt endl

if ( (a lt 2) ampamp (3 lt a) )

cout ltlt a is less than 2 AND greater than 3 (impossible) ltlt endl

1237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

What if we want to execute more than one statement

We look at what defines a statement

if ( true ) cout ltlt The condition is true ltlt endl

else cout ltlt The condition is false ltlt endl

if ( a gt 3 )

cout ltlt a is greater than 3 ltlt endl

cout ltlt And we can do other things ltlt endl

else

cout ltlt a is NOT greater than 3 ltlt endl

cout ltlt As well when the condition is false ltlt endl

1337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Basic looping structures

while loopwhile ( conditional) statements with changerfor loopfor (initial conditional changer) statements

do while loopdo statements with changer while (conditional)

Handcrafted (which we wonrsquot go into)

1437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

The ldquoinfiniterdquo loop

There may be times when you want a loop to repeat but theterminate conditions are too hard to make into a set ofcomparisonsstdstring fileName = tmptemptxt

stdifstream inputFile

int data = 0

inputFileopen(fileNamec_str())

for ( )

data ltlt inputFile

if (data == 37)

break

else

if ( data == 16)

continue

data += 42

break ldquobreaksrdquo out of the current control structure continue

ldquocontinuesrdquo execution at the top of the control structure

1537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

What if there is more than one ldquootherrdquo case

The ldquoifrdquo statement handles exactly one conditional and thenexecutes code based on whether that conditional is ldquotruerdquo orldquofalserdquoldquoifrdquo statements can be nested to create very complex conditionalexpressionsBut how can we efficiently handle many conditionals at onceEnter the ldquoswitchrdquo statement The ldquoswitchrdquo statementcompares one expression against a number of conditions andexecutes code when the condition is true Wersquoll play with the

ifcpp and switchcpp programs

1637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Notional ldquoswitchrdquo structure structure

The ldquoswitch statement is aselection control structure formulti-way branching

IntegralExpression ndash anyexpression that can bereduced to an integer value

case Constant ndash anyconstant value that is thesame type as theIntegralExpression

default ndash the ldquocaserdquo whenno other cases match

Image from [2]

1737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Same image

Image from [2]

1837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Example of a ldquoswitchrdquo statement

cin gtgt letter gtgt first gtgt second

switch (letter)

case rsquoArsquo

answer = (first + second)

cout ltlt first ltlt + ltlt second

ltlt is ltlt answer ltlt endl

break

case rsquoSrsquo

answer = (first - second)

cout ltlt first ltlt - ltlt second

ltlt is ltlt answer ltlt endl

break

1937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

More details about the switch statement

The value ofIntegralExpression (of charshort int long or enumtype) determines whichbranch is executed

Case labels are constantintegral expressions

Several case labels canprecede a statement

Control branches to thestatement following thecase label that matches the

value of IntegralExpression

Control proceeds throughall remaining statementsincluding the defaultunless redirected with break

If no case label matches thevalue of IntegralExpressioncontrol branches to thedefault label if present

Otherwise control passes tothe statement following theentire switch statement

Forgetting to use break can cause logical errors

2037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Misc things about break and continue statements

A break statement can beused in switch or any ofthe 3 looping structures

It causes an immediateexit from the currentstructure

If used in a nestedstructure it only exitsthe current structure

A continue statement canonly be used in a loopingstructure

It terminates the currentiteration but not theentire loopIn a ldquoforrdquo loop theupdate is still doneIn a ldquodo ndash whilerdquo theexit condition is tested

Indiscriminate use of break and continue can lead to confusingcode

2137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

C++ operators we will know and love

There are a lot of declaredoperators in C++ Over the nextfew months will will learn aboutthe ones in red and possibly theones in green

Image from [1]

2237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [1]

2337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Specialized C++ operators

What do these expressions do and why

Interesting expressions232 (alpha + beta)delta = 2 12

Confusing expressions

int1 = 14 int2 =++int1

int1 = 14 int2 =int1++

When in doubt fire up CodeBlocks and test them out

2837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

Bit operators

What do these fragments produce and why

When in doubt fire up CodeBlocks and test them out

2937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What if we donrsquot like the type of our variable

There may be some cases where we want the compiler to changethe ldquotyperdquo of our dataThis is known as ldquocastingrdquo the variable It really is changing thevalue of the variable to the desired type

Functional notationintVar = int(floatVar)

Prefix notationintVar = (int) floatVar

Keyword notationintVar = static castltintgt(floatVar)

Keyword notation is gaining popularity because it is easy to locatein multiple files

3037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What are the mechanics behind ldquocastingrdquo values

There are only two cases

If there is only one data type involved

Trivial case nothing happens

If there is more than one data type involved

Each data type is promoted to the next higher data typeuntil we have a trivial caseOrder of data type promotion int unsigned int long

float double long double

Casting also happens behind the scenes with conditionals Bestadvice is to compare like types

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

This and that

Read from a file

Objectives are fairly straightforward

Read strings from a data file

First string is the key

Second string is the plain text

Output plain and ldquoencryptedrdquostrings to the screen in a particularorder

Submit your source code

This is a single person effort (not ateam effort)

Any questions or problems

1037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Flow of control

There are limited number of different ldquoflow of controlrdquo

Sequential ndash instructions are executed in order

Function calls ndash program execution is transferred to a functionand then returned (with or without a return value)

Selection ndash some instructions are executed but others are not

Looping ndash a set of instructions is executed more than once

1137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

The ldquoifrdquo statement

The ldquoifrdquo statement evaluates a conditional as ldquotruerdquo orldquofalserdquoWhen the conditional is ldquotruerdquo then the next statement isexecutedThe conditional can be simple or complex

Examples of ldquoifrdquo statementsif ( true ) cout ltlt The condition is true ltlt endl

if ( true )

cout ltlt The condition is true ltlt endl

if ( a gt 3 )

cout ltlt a is greater than 3 ltlt endl

if ( (a lt 2) || (3 lt a) )

cout ltlt a is less than 2 OR greater than 3 ltlt endl

if ( (a lt 2) ampamp (3 lt a) )

cout ltlt a is less than 2 AND greater than 3 (impossible) ltlt endl

1237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

What if we want to execute more than one statement

We look at what defines a statement

if ( true ) cout ltlt The condition is true ltlt endl

else cout ltlt The condition is false ltlt endl

if ( a gt 3 )

cout ltlt a is greater than 3 ltlt endl

cout ltlt And we can do other things ltlt endl

else

cout ltlt a is NOT greater than 3 ltlt endl

cout ltlt As well when the condition is false ltlt endl

1337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Basic looping structures

while loopwhile ( conditional) statements with changerfor loopfor (initial conditional changer) statements

do while loopdo statements with changer while (conditional)

Handcrafted (which we wonrsquot go into)

1437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

The ldquoinfiniterdquo loop

There may be times when you want a loop to repeat but theterminate conditions are too hard to make into a set ofcomparisonsstdstring fileName = tmptemptxt

stdifstream inputFile

int data = 0

inputFileopen(fileNamec_str())

for ( )

data ltlt inputFile

if (data == 37)

break

else

if ( data == 16)

continue

data += 42

break ldquobreaksrdquo out of the current control structure continue

ldquocontinuesrdquo execution at the top of the control structure

1537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

What if there is more than one ldquootherrdquo case

The ldquoifrdquo statement handles exactly one conditional and thenexecutes code based on whether that conditional is ldquotruerdquo orldquofalserdquoldquoifrdquo statements can be nested to create very complex conditionalexpressionsBut how can we efficiently handle many conditionals at onceEnter the ldquoswitchrdquo statement The ldquoswitchrdquo statementcompares one expression against a number of conditions andexecutes code when the condition is true Wersquoll play with the

ifcpp and switchcpp programs

1637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Notional ldquoswitchrdquo structure structure

The ldquoswitch statement is aselection control structure formulti-way branching

IntegralExpression ndash anyexpression that can bereduced to an integer value

case Constant ndash anyconstant value that is thesame type as theIntegralExpression

default ndash the ldquocaserdquo whenno other cases match

Image from [2]

1737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Same image

Image from [2]

1837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Example of a ldquoswitchrdquo statement

cin gtgt letter gtgt first gtgt second

switch (letter)

case rsquoArsquo

answer = (first + second)

cout ltlt first ltlt + ltlt second

ltlt is ltlt answer ltlt endl

break

case rsquoSrsquo

answer = (first - second)

cout ltlt first ltlt - ltlt second

ltlt is ltlt answer ltlt endl

break

1937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

More details about the switch statement

The value ofIntegralExpression (of charshort int long or enumtype) determines whichbranch is executed

Case labels are constantintegral expressions

Several case labels canprecede a statement

Control branches to thestatement following thecase label that matches the

value of IntegralExpression

Control proceeds throughall remaining statementsincluding the defaultunless redirected with break

If no case label matches thevalue of IntegralExpressioncontrol branches to thedefault label if present

Otherwise control passes tothe statement following theentire switch statement

Forgetting to use break can cause logical errors

2037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Misc things about break and continue statements

A break statement can beused in switch or any ofthe 3 looping structures

It causes an immediateexit from the currentstructure

If used in a nestedstructure it only exitsthe current structure

A continue statement canonly be used in a loopingstructure

It terminates the currentiteration but not theentire loopIn a ldquoforrdquo loop theupdate is still doneIn a ldquodo ndash whilerdquo theexit condition is tested

Indiscriminate use of break and continue can lead to confusingcode

2137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

C++ operators we will know and love

There are a lot of declaredoperators in C++ Over the nextfew months will will learn aboutthe ones in red and possibly theones in green

Image from [1]

2237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [1]

2337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Specialized C++ operators

What do these expressions do and why

Interesting expressions232 (alpha + beta)delta = 2 12

Confusing expressions

int1 = 14 int2 =++int1

int1 = 14 int2 =int1++

When in doubt fire up CodeBlocks and test them out

2837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

Bit operators

What do these fragments produce and why

When in doubt fire up CodeBlocks and test them out

2937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What if we donrsquot like the type of our variable

There may be some cases where we want the compiler to changethe ldquotyperdquo of our dataThis is known as ldquocastingrdquo the variable It really is changing thevalue of the variable to the desired type

Functional notationintVar = int(floatVar)

Prefix notationintVar = (int) floatVar

Keyword notationintVar = static castltintgt(floatVar)

Keyword notation is gaining popularity because it is easy to locatein multiple files

3037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What are the mechanics behind ldquocastingrdquo values

There are only two cases

If there is only one data type involved

Trivial case nothing happens

If there is more than one data type involved

Each data type is promoted to the next higher data typeuntil we have a trivial caseOrder of data type promotion int unsigned int long

float double long double

Casting also happens behind the scenes with conditionals Bestadvice is to compare like types

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

1037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Flow of control

There are limited number of different ldquoflow of controlrdquo

Sequential ndash instructions are executed in order

Function calls ndash program execution is transferred to a functionand then returned (with or without a return value)

Selection ndash some instructions are executed but others are not

Looping ndash a set of instructions is executed more than once

1137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

The ldquoifrdquo statement

The ldquoifrdquo statement evaluates a conditional as ldquotruerdquo orldquofalserdquoWhen the conditional is ldquotruerdquo then the next statement isexecutedThe conditional can be simple or complex

Examples of ldquoifrdquo statementsif ( true ) cout ltlt The condition is true ltlt endl

if ( true )

cout ltlt The condition is true ltlt endl

if ( a gt 3 )

cout ltlt a is greater than 3 ltlt endl

if ( (a lt 2) || (3 lt a) )

cout ltlt a is less than 2 OR greater than 3 ltlt endl

if ( (a lt 2) ampamp (3 lt a) )

cout ltlt a is less than 2 AND greater than 3 (impossible) ltlt endl

1237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

What if we want to execute more than one statement

We look at what defines a statement

if ( true ) cout ltlt The condition is true ltlt endl

else cout ltlt The condition is false ltlt endl

if ( a gt 3 )

cout ltlt a is greater than 3 ltlt endl

cout ltlt And we can do other things ltlt endl

else

cout ltlt a is NOT greater than 3 ltlt endl

cout ltlt As well when the condition is false ltlt endl

1337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Basic looping structures

while loopwhile ( conditional) statements with changerfor loopfor (initial conditional changer) statements

do while loopdo statements with changer while (conditional)

Handcrafted (which we wonrsquot go into)

1437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

The ldquoinfiniterdquo loop

There may be times when you want a loop to repeat but theterminate conditions are too hard to make into a set ofcomparisonsstdstring fileName = tmptemptxt

stdifstream inputFile

int data = 0

inputFileopen(fileNamec_str())

for ( )

data ltlt inputFile

if (data == 37)

break

else

if ( data == 16)

continue

data += 42

break ldquobreaksrdquo out of the current control structure continue

ldquocontinuesrdquo execution at the top of the control structure

1537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

What if there is more than one ldquootherrdquo case

The ldquoifrdquo statement handles exactly one conditional and thenexecutes code based on whether that conditional is ldquotruerdquo orldquofalserdquoldquoifrdquo statements can be nested to create very complex conditionalexpressionsBut how can we efficiently handle many conditionals at onceEnter the ldquoswitchrdquo statement The ldquoswitchrdquo statementcompares one expression against a number of conditions andexecutes code when the condition is true Wersquoll play with the

ifcpp and switchcpp programs

1637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Notional ldquoswitchrdquo structure structure

The ldquoswitch statement is aselection control structure formulti-way branching

IntegralExpression ndash anyexpression that can bereduced to an integer value

case Constant ndash anyconstant value that is thesame type as theIntegralExpression

default ndash the ldquocaserdquo whenno other cases match

Image from [2]

1737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Same image

Image from [2]

1837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Example of a ldquoswitchrdquo statement

cin gtgt letter gtgt first gtgt second

switch (letter)

case rsquoArsquo

answer = (first + second)

cout ltlt first ltlt + ltlt second

ltlt is ltlt answer ltlt endl

break

case rsquoSrsquo

answer = (first - second)

cout ltlt first ltlt - ltlt second

ltlt is ltlt answer ltlt endl

break

1937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

More details about the switch statement

The value ofIntegralExpression (of charshort int long or enumtype) determines whichbranch is executed

Case labels are constantintegral expressions

Several case labels canprecede a statement

Control branches to thestatement following thecase label that matches the

value of IntegralExpression

Control proceeds throughall remaining statementsincluding the defaultunless redirected with break

If no case label matches thevalue of IntegralExpressioncontrol branches to thedefault label if present

Otherwise control passes tothe statement following theentire switch statement

Forgetting to use break can cause logical errors

2037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Misc things about break and continue statements

A break statement can beused in switch or any ofthe 3 looping structures

It causes an immediateexit from the currentstructure

If used in a nestedstructure it only exitsthe current structure

A continue statement canonly be used in a loopingstructure

It terminates the currentiteration but not theentire loopIn a ldquoforrdquo loop theupdate is still doneIn a ldquodo ndash whilerdquo theexit condition is tested

Indiscriminate use of break and continue can lead to confusingcode

2137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

C++ operators we will know and love

There are a lot of declaredoperators in C++ Over the nextfew months will will learn aboutthe ones in red and possibly theones in green

Image from [1]

2237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [1]

2337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Specialized C++ operators

What do these expressions do and why

Interesting expressions232 (alpha + beta)delta = 2 12

Confusing expressions

int1 = 14 int2 =++int1

int1 = 14 int2 =int1++

When in doubt fire up CodeBlocks and test them out

2837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

Bit operators

What do these fragments produce and why

When in doubt fire up CodeBlocks and test them out

2937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What if we donrsquot like the type of our variable

There may be some cases where we want the compiler to changethe ldquotyperdquo of our dataThis is known as ldquocastingrdquo the variable It really is changing thevalue of the variable to the desired type

Functional notationintVar = int(floatVar)

Prefix notationintVar = (int) floatVar

Keyword notationintVar = static castltintgt(floatVar)

Keyword notation is gaining popularity because it is easy to locatein multiple files

3037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What are the mechanics behind ldquocastingrdquo values

There are only two cases

If there is only one data type involved

Trivial case nothing happens

If there is more than one data type involved

Each data type is promoted to the next higher data typeuntil we have a trivial caseOrder of data type promotion int unsigned int long

float double long double

Casting also happens behind the scenes with conditionals Bestadvice is to compare like types

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

1137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

The ldquoifrdquo statement

The ldquoifrdquo statement evaluates a conditional as ldquotruerdquo orldquofalserdquoWhen the conditional is ldquotruerdquo then the next statement isexecutedThe conditional can be simple or complex

Examples of ldquoifrdquo statementsif ( true ) cout ltlt The condition is true ltlt endl

if ( true )

cout ltlt The condition is true ltlt endl

if ( a gt 3 )

cout ltlt a is greater than 3 ltlt endl

if ( (a lt 2) || (3 lt a) )

cout ltlt a is less than 2 OR greater than 3 ltlt endl

if ( (a lt 2) ampamp (3 lt a) )

cout ltlt a is less than 2 AND greater than 3 (impossible) ltlt endl

1237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

What if we want to execute more than one statement

We look at what defines a statement

if ( true ) cout ltlt The condition is true ltlt endl

else cout ltlt The condition is false ltlt endl

if ( a gt 3 )

cout ltlt a is greater than 3 ltlt endl

cout ltlt And we can do other things ltlt endl

else

cout ltlt a is NOT greater than 3 ltlt endl

cout ltlt As well when the condition is false ltlt endl

1337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Basic looping structures

while loopwhile ( conditional) statements with changerfor loopfor (initial conditional changer) statements

do while loopdo statements with changer while (conditional)

Handcrafted (which we wonrsquot go into)

1437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

The ldquoinfiniterdquo loop

There may be times when you want a loop to repeat but theterminate conditions are too hard to make into a set ofcomparisonsstdstring fileName = tmptemptxt

stdifstream inputFile

int data = 0

inputFileopen(fileNamec_str())

for ( )

data ltlt inputFile

if (data == 37)

break

else

if ( data == 16)

continue

data += 42

break ldquobreaksrdquo out of the current control structure continue

ldquocontinuesrdquo execution at the top of the control structure

1537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

What if there is more than one ldquootherrdquo case

The ldquoifrdquo statement handles exactly one conditional and thenexecutes code based on whether that conditional is ldquotruerdquo orldquofalserdquoldquoifrdquo statements can be nested to create very complex conditionalexpressionsBut how can we efficiently handle many conditionals at onceEnter the ldquoswitchrdquo statement The ldquoswitchrdquo statementcompares one expression against a number of conditions andexecutes code when the condition is true Wersquoll play with the

ifcpp and switchcpp programs

1637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Notional ldquoswitchrdquo structure structure

The ldquoswitch statement is aselection control structure formulti-way branching

IntegralExpression ndash anyexpression that can bereduced to an integer value

case Constant ndash anyconstant value that is thesame type as theIntegralExpression

default ndash the ldquocaserdquo whenno other cases match

Image from [2]

1737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Same image

Image from [2]

1837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Example of a ldquoswitchrdquo statement

cin gtgt letter gtgt first gtgt second

switch (letter)

case rsquoArsquo

answer = (first + second)

cout ltlt first ltlt + ltlt second

ltlt is ltlt answer ltlt endl

break

case rsquoSrsquo

answer = (first - second)

cout ltlt first ltlt - ltlt second

ltlt is ltlt answer ltlt endl

break

1937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

More details about the switch statement

The value ofIntegralExpression (of charshort int long or enumtype) determines whichbranch is executed

Case labels are constantintegral expressions

Several case labels canprecede a statement

Control branches to thestatement following thecase label that matches the

value of IntegralExpression

Control proceeds throughall remaining statementsincluding the defaultunless redirected with break

If no case label matches thevalue of IntegralExpressioncontrol branches to thedefault label if present

Otherwise control passes tothe statement following theentire switch statement

Forgetting to use break can cause logical errors

2037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Misc things about break and continue statements

A break statement can beused in switch or any ofthe 3 looping structures

It causes an immediateexit from the currentstructure

If used in a nestedstructure it only exitsthe current structure

A continue statement canonly be used in a loopingstructure

It terminates the currentiteration but not theentire loopIn a ldquoforrdquo loop theupdate is still doneIn a ldquodo ndash whilerdquo theexit condition is tested

Indiscriminate use of break and continue can lead to confusingcode

2137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

C++ operators we will know and love

There are a lot of declaredoperators in C++ Over the nextfew months will will learn aboutthe ones in red and possibly theones in green

Image from [1]

2237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [1]

2337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Specialized C++ operators

What do these expressions do and why

Interesting expressions232 (alpha + beta)delta = 2 12

Confusing expressions

int1 = 14 int2 =++int1

int1 = 14 int2 =int1++

When in doubt fire up CodeBlocks and test them out

2837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

Bit operators

What do these fragments produce and why

When in doubt fire up CodeBlocks and test them out

2937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What if we donrsquot like the type of our variable

There may be some cases where we want the compiler to changethe ldquotyperdquo of our dataThis is known as ldquocastingrdquo the variable It really is changing thevalue of the variable to the desired type

Functional notationintVar = int(floatVar)

Prefix notationintVar = (int) floatVar

Keyword notationintVar = static castltintgt(floatVar)

Keyword notation is gaining popularity because it is easy to locatein multiple files

3037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What are the mechanics behind ldquocastingrdquo values

There are only two cases

If there is only one data type involved

Trivial case nothing happens

If there is more than one data type involved

Each data type is promoted to the next higher data typeuntil we have a trivial caseOrder of data type promotion int unsigned int long

float double long double

Casting also happens behind the scenes with conditionals Bestadvice is to compare like types

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

1237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

What if we want to execute more than one statement

We look at what defines a statement

if ( true ) cout ltlt The condition is true ltlt endl

else cout ltlt The condition is false ltlt endl

if ( a gt 3 )

cout ltlt a is greater than 3 ltlt endl

cout ltlt And we can do other things ltlt endl

else

cout ltlt a is NOT greater than 3 ltlt endl

cout ltlt As well when the condition is false ltlt endl

1337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Basic looping structures

while loopwhile ( conditional) statements with changerfor loopfor (initial conditional changer) statements

do while loopdo statements with changer while (conditional)

Handcrafted (which we wonrsquot go into)

1437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

The ldquoinfiniterdquo loop

There may be times when you want a loop to repeat but theterminate conditions are too hard to make into a set ofcomparisonsstdstring fileName = tmptemptxt

stdifstream inputFile

int data = 0

inputFileopen(fileNamec_str())

for ( )

data ltlt inputFile

if (data == 37)

break

else

if ( data == 16)

continue

data += 42

break ldquobreaksrdquo out of the current control structure continue

ldquocontinuesrdquo execution at the top of the control structure

1537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

What if there is more than one ldquootherrdquo case

The ldquoifrdquo statement handles exactly one conditional and thenexecutes code based on whether that conditional is ldquotruerdquo orldquofalserdquoldquoifrdquo statements can be nested to create very complex conditionalexpressionsBut how can we efficiently handle many conditionals at onceEnter the ldquoswitchrdquo statement The ldquoswitchrdquo statementcompares one expression against a number of conditions andexecutes code when the condition is true Wersquoll play with the

ifcpp and switchcpp programs

1637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Notional ldquoswitchrdquo structure structure

The ldquoswitch statement is aselection control structure formulti-way branching

IntegralExpression ndash anyexpression that can bereduced to an integer value

case Constant ndash anyconstant value that is thesame type as theIntegralExpression

default ndash the ldquocaserdquo whenno other cases match

Image from [2]

1737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Same image

Image from [2]

1837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Example of a ldquoswitchrdquo statement

cin gtgt letter gtgt first gtgt second

switch (letter)

case rsquoArsquo

answer = (first + second)

cout ltlt first ltlt + ltlt second

ltlt is ltlt answer ltlt endl

break

case rsquoSrsquo

answer = (first - second)

cout ltlt first ltlt - ltlt second

ltlt is ltlt answer ltlt endl

break

1937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

More details about the switch statement

The value ofIntegralExpression (of charshort int long or enumtype) determines whichbranch is executed

Case labels are constantintegral expressions

Several case labels canprecede a statement

Control branches to thestatement following thecase label that matches the

value of IntegralExpression

Control proceeds throughall remaining statementsincluding the defaultunless redirected with break

If no case label matches thevalue of IntegralExpressioncontrol branches to thedefault label if present

Otherwise control passes tothe statement following theentire switch statement

Forgetting to use break can cause logical errors

2037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Misc things about break and continue statements

A break statement can beused in switch or any ofthe 3 looping structures

It causes an immediateexit from the currentstructure

If used in a nestedstructure it only exitsthe current structure

A continue statement canonly be used in a loopingstructure

It terminates the currentiteration but not theentire loopIn a ldquoforrdquo loop theupdate is still doneIn a ldquodo ndash whilerdquo theexit condition is tested

Indiscriminate use of break and continue can lead to confusingcode

2137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

C++ operators we will know and love

There are a lot of declaredoperators in C++ Over the nextfew months will will learn aboutthe ones in red and possibly theones in green

Image from [1]

2237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [1]

2337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Specialized C++ operators

What do these expressions do and why

Interesting expressions232 (alpha + beta)delta = 2 12

Confusing expressions

int1 = 14 int2 =++int1

int1 = 14 int2 =int1++

When in doubt fire up CodeBlocks and test them out

2837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

Bit operators

What do these fragments produce and why

When in doubt fire up CodeBlocks and test them out

2937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What if we donrsquot like the type of our variable

There may be some cases where we want the compiler to changethe ldquotyperdquo of our dataThis is known as ldquocastingrdquo the variable It really is changing thevalue of the variable to the desired type

Functional notationintVar = int(floatVar)

Prefix notationintVar = (int) floatVar

Keyword notationintVar = static castltintgt(floatVar)

Keyword notation is gaining popularity because it is easy to locatein multiple files

3037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What are the mechanics behind ldquocastingrdquo values

There are only two cases

If there is only one data type involved

Trivial case nothing happens

If there is more than one data type involved

Each data type is promoted to the next higher data typeuntil we have a trivial caseOrder of data type promotion int unsigned int long

float double long double

Casting also happens behind the scenes with conditionals Bestadvice is to compare like types

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

1337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Basic looping structures

while loopwhile ( conditional) statements with changerfor loopfor (initial conditional changer) statements

do while loopdo statements with changer while (conditional)

Handcrafted (which we wonrsquot go into)

1437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

The ldquoinfiniterdquo loop

There may be times when you want a loop to repeat but theterminate conditions are too hard to make into a set ofcomparisonsstdstring fileName = tmptemptxt

stdifstream inputFile

int data = 0

inputFileopen(fileNamec_str())

for ( )

data ltlt inputFile

if (data == 37)

break

else

if ( data == 16)

continue

data += 42

break ldquobreaksrdquo out of the current control structure continue

ldquocontinuesrdquo execution at the top of the control structure

1537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

What if there is more than one ldquootherrdquo case

The ldquoifrdquo statement handles exactly one conditional and thenexecutes code based on whether that conditional is ldquotruerdquo orldquofalserdquoldquoifrdquo statements can be nested to create very complex conditionalexpressionsBut how can we efficiently handle many conditionals at onceEnter the ldquoswitchrdquo statement The ldquoswitchrdquo statementcompares one expression against a number of conditions andexecutes code when the condition is true Wersquoll play with the

ifcpp and switchcpp programs

1637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Notional ldquoswitchrdquo structure structure

The ldquoswitch statement is aselection control structure formulti-way branching

IntegralExpression ndash anyexpression that can bereduced to an integer value

case Constant ndash anyconstant value that is thesame type as theIntegralExpression

default ndash the ldquocaserdquo whenno other cases match

Image from [2]

1737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Same image

Image from [2]

1837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Example of a ldquoswitchrdquo statement

cin gtgt letter gtgt first gtgt second

switch (letter)

case rsquoArsquo

answer = (first + second)

cout ltlt first ltlt + ltlt second

ltlt is ltlt answer ltlt endl

break

case rsquoSrsquo

answer = (first - second)

cout ltlt first ltlt - ltlt second

ltlt is ltlt answer ltlt endl

break

1937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

More details about the switch statement

The value ofIntegralExpression (of charshort int long or enumtype) determines whichbranch is executed

Case labels are constantintegral expressions

Several case labels canprecede a statement

Control branches to thestatement following thecase label that matches the

value of IntegralExpression

Control proceeds throughall remaining statementsincluding the defaultunless redirected with break

If no case label matches thevalue of IntegralExpressioncontrol branches to thedefault label if present

Otherwise control passes tothe statement following theentire switch statement

Forgetting to use break can cause logical errors

2037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Misc things about break and continue statements

A break statement can beused in switch or any ofthe 3 looping structures

It causes an immediateexit from the currentstructure

If used in a nestedstructure it only exitsthe current structure

A continue statement canonly be used in a loopingstructure

It terminates the currentiteration but not theentire loopIn a ldquoforrdquo loop theupdate is still doneIn a ldquodo ndash whilerdquo theexit condition is tested

Indiscriminate use of break and continue can lead to confusingcode

2137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

C++ operators we will know and love

There are a lot of declaredoperators in C++ Over the nextfew months will will learn aboutthe ones in red and possibly theones in green

Image from [1]

2237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [1]

2337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Specialized C++ operators

What do these expressions do and why

Interesting expressions232 (alpha + beta)delta = 2 12

Confusing expressions

int1 = 14 int2 =++int1

int1 = 14 int2 =int1++

When in doubt fire up CodeBlocks and test them out

2837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

Bit operators

What do these fragments produce and why

When in doubt fire up CodeBlocks and test them out

2937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What if we donrsquot like the type of our variable

There may be some cases where we want the compiler to changethe ldquotyperdquo of our dataThis is known as ldquocastingrdquo the variable It really is changing thevalue of the variable to the desired type

Functional notationintVar = int(floatVar)

Prefix notationintVar = (int) floatVar

Keyword notationintVar = static castltintgt(floatVar)

Keyword notation is gaining popularity because it is easy to locatein multiple files

3037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What are the mechanics behind ldquocastingrdquo values

There are only two cases

If there is only one data type involved

Trivial case nothing happens

If there is more than one data type involved

Each data type is promoted to the next higher data typeuntil we have a trivial caseOrder of data type promotion int unsigned int long

float double long double

Casting also happens behind the scenes with conditionals Bestadvice is to compare like types

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

1437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

The ldquoinfiniterdquo loop

There may be times when you want a loop to repeat but theterminate conditions are too hard to make into a set ofcomparisonsstdstring fileName = tmptemptxt

stdifstream inputFile

int data = 0

inputFileopen(fileNamec_str())

for ( )

data ltlt inputFile

if (data == 37)

break

else

if ( data == 16)

continue

data += 42

break ldquobreaksrdquo out of the current control structure continue

ldquocontinuesrdquo execution at the top of the control structure

1537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

What if there is more than one ldquootherrdquo case

The ldquoifrdquo statement handles exactly one conditional and thenexecutes code based on whether that conditional is ldquotruerdquo orldquofalserdquoldquoifrdquo statements can be nested to create very complex conditionalexpressionsBut how can we efficiently handle many conditionals at onceEnter the ldquoswitchrdquo statement The ldquoswitchrdquo statementcompares one expression against a number of conditions andexecutes code when the condition is true Wersquoll play with the

ifcpp and switchcpp programs

1637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Notional ldquoswitchrdquo structure structure

The ldquoswitch statement is aselection control structure formulti-way branching

IntegralExpression ndash anyexpression that can bereduced to an integer value

case Constant ndash anyconstant value that is thesame type as theIntegralExpression

default ndash the ldquocaserdquo whenno other cases match

Image from [2]

1737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Same image

Image from [2]

1837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Example of a ldquoswitchrdquo statement

cin gtgt letter gtgt first gtgt second

switch (letter)

case rsquoArsquo

answer = (first + second)

cout ltlt first ltlt + ltlt second

ltlt is ltlt answer ltlt endl

break

case rsquoSrsquo

answer = (first - second)

cout ltlt first ltlt - ltlt second

ltlt is ltlt answer ltlt endl

break

1937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

More details about the switch statement

The value ofIntegralExpression (of charshort int long or enumtype) determines whichbranch is executed

Case labels are constantintegral expressions

Several case labels canprecede a statement

Control branches to thestatement following thecase label that matches the

value of IntegralExpression

Control proceeds throughall remaining statementsincluding the defaultunless redirected with break

If no case label matches thevalue of IntegralExpressioncontrol branches to thedefault label if present

Otherwise control passes tothe statement following theentire switch statement

Forgetting to use break can cause logical errors

2037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Misc things about break and continue statements

A break statement can beused in switch or any ofthe 3 looping structures

It causes an immediateexit from the currentstructure

If used in a nestedstructure it only exitsthe current structure

A continue statement canonly be used in a loopingstructure

It terminates the currentiteration but not theentire loopIn a ldquoforrdquo loop theupdate is still doneIn a ldquodo ndash whilerdquo theexit condition is tested

Indiscriminate use of break and continue can lead to confusingcode

2137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

C++ operators we will know and love

There are a lot of declaredoperators in C++ Over the nextfew months will will learn aboutthe ones in red and possibly theones in green

Image from [1]

2237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [1]

2337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Specialized C++ operators

What do these expressions do and why

Interesting expressions232 (alpha + beta)delta = 2 12

Confusing expressions

int1 = 14 int2 =++int1

int1 = 14 int2 =int1++

When in doubt fire up CodeBlocks and test them out

2837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

Bit operators

What do these fragments produce and why

When in doubt fire up CodeBlocks and test them out

2937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What if we donrsquot like the type of our variable

There may be some cases where we want the compiler to changethe ldquotyperdquo of our dataThis is known as ldquocastingrdquo the variable It really is changing thevalue of the variable to the desired type

Functional notationintVar = int(floatVar)

Prefix notationintVar = (int) floatVar

Keyword notationintVar = static castltintgt(floatVar)

Keyword notation is gaining popularity because it is easy to locatein multiple files

3037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What are the mechanics behind ldquocastingrdquo values

There are only two cases

If there is only one data type involved

Trivial case nothing happens

If there is more than one data type involved

Each data type is promoted to the next higher data typeuntil we have a trivial caseOrder of data type promotion int unsigned int long

float double long double

Casting also happens behind the scenes with conditionals Bestadvice is to compare like types

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

1537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

What if there is more than one ldquootherrdquo case

The ldquoifrdquo statement handles exactly one conditional and thenexecutes code based on whether that conditional is ldquotruerdquo orldquofalserdquoldquoifrdquo statements can be nested to create very complex conditionalexpressionsBut how can we efficiently handle many conditionals at onceEnter the ldquoswitchrdquo statement The ldquoswitchrdquo statementcompares one expression against a number of conditions andexecutes code when the condition is true Wersquoll play with the

ifcpp and switchcpp programs

1637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Notional ldquoswitchrdquo structure structure

The ldquoswitch statement is aselection control structure formulti-way branching

IntegralExpression ndash anyexpression that can bereduced to an integer value

case Constant ndash anyconstant value that is thesame type as theIntegralExpression

default ndash the ldquocaserdquo whenno other cases match

Image from [2]

1737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Same image

Image from [2]

1837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Example of a ldquoswitchrdquo statement

cin gtgt letter gtgt first gtgt second

switch (letter)

case rsquoArsquo

answer = (first + second)

cout ltlt first ltlt + ltlt second

ltlt is ltlt answer ltlt endl

break

case rsquoSrsquo

answer = (first - second)

cout ltlt first ltlt - ltlt second

ltlt is ltlt answer ltlt endl

break

1937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

More details about the switch statement

The value ofIntegralExpression (of charshort int long or enumtype) determines whichbranch is executed

Case labels are constantintegral expressions

Several case labels canprecede a statement

Control branches to thestatement following thecase label that matches the

value of IntegralExpression

Control proceeds throughall remaining statementsincluding the defaultunless redirected with break

If no case label matches thevalue of IntegralExpressioncontrol branches to thedefault label if present

Otherwise control passes tothe statement following theentire switch statement

Forgetting to use break can cause logical errors

2037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Misc things about break and continue statements

A break statement can beused in switch or any ofthe 3 looping structures

It causes an immediateexit from the currentstructure

If used in a nestedstructure it only exitsthe current structure

A continue statement canonly be used in a loopingstructure

It terminates the currentiteration but not theentire loopIn a ldquoforrdquo loop theupdate is still doneIn a ldquodo ndash whilerdquo theexit condition is tested

Indiscriminate use of break and continue can lead to confusingcode

2137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

C++ operators we will know and love

There are a lot of declaredoperators in C++ Over the nextfew months will will learn aboutthe ones in red and possibly theones in green

Image from [1]

2237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [1]

2337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Specialized C++ operators

What do these expressions do and why

Interesting expressions232 (alpha + beta)delta = 2 12

Confusing expressions

int1 = 14 int2 =++int1

int1 = 14 int2 =int1++

When in doubt fire up CodeBlocks and test them out

2837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

Bit operators

What do these fragments produce and why

When in doubt fire up CodeBlocks and test them out

2937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What if we donrsquot like the type of our variable

There may be some cases where we want the compiler to changethe ldquotyperdquo of our dataThis is known as ldquocastingrdquo the variable It really is changing thevalue of the variable to the desired type

Functional notationintVar = int(floatVar)

Prefix notationintVar = (int) floatVar

Keyword notationintVar = static castltintgt(floatVar)

Keyword notation is gaining popularity because it is easy to locatein multiple files

3037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What are the mechanics behind ldquocastingrdquo values

There are only two cases

If there is only one data type involved

Trivial case nothing happens

If there is more than one data type involved

Each data type is promoted to the next higher data typeuntil we have a trivial caseOrder of data type promotion int unsigned int long

float double long double

Casting also happens behind the scenes with conditionals Bestadvice is to compare like types

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

1637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Notional ldquoswitchrdquo structure structure

The ldquoswitch statement is aselection control structure formulti-way branching

IntegralExpression ndash anyexpression that can bereduced to an integer value

case Constant ndash anyconstant value that is thesame type as theIntegralExpression

default ndash the ldquocaserdquo whenno other cases match

Image from [2]

1737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Same image

Image from [2]

1837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Example of a ldquoswitchrdquo statement

cin gtgt letter gtgt first gtgt second

switch (letter)

case rsquoArsquo

answer = (first + second)

cout ltlt first ltlt + ltlt second

ltlt is ltlt answer ltlt endl

break

case rsquoSrsquo

answer = (first - second)

cout ltlt first ltlt - ltlt second

ltlt is ltlt answer ltlt endl

break

1937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

More details about the switch statement

The value ofIntegralExpression (of charshort int long or enumtype) determines whichbranch is executed

Case labels are constantintegral expressions

Several case labels canprecede a statement

Control branches to thestatement following thecase label that matches the

value of IntegralExpression

Control proceeds throughall remaining statementsincluding the defaultunless redirected with break

If no case label matches thevalue of IntegralExpressioncontrol branches to thedefault label if present

Otherwise control passes tothe statement following theentire switch statement

Forgetting to use break can cause logical errors

2037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Misc things about break and continue statements

A break statement can beused in switch or any ofthe 3 looping structures

It causes an immediateexit from the currentstructure

If used in a nestedstructure it only exitsthe current structure

A continue statement canonly be used in a loopingstructure

It terminates the currentiteration but not theentire loopIn a ldquoforrdquo loop theupdate is still doneIn a ldquodo ndash whilerdquo theexit condition is tested

Indiscriminate use of break and continue can lead to confusingcode

2137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

C++ operators we will know and love

There are a lot of declaredoperators in C++ Over the nextfew months will will learn aboutthe ones in red and possibly theones in green

Image from [1]

2237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [1]

2337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Specialized C++ operators

What do these expressions do and why

Interesting expressions232 (alpha + beta)delta = 2 12

Confusing expressions

int1 = 14 int2 =++int1

int1 = 14 int2 =int1++

When in doubt fire up CodeBlocks and test them out

2837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

Bit operators

What do these fragments produce and why

When in doubt fire up CodeBlocks and test them out

2937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What if we donrsquot like the type of our variable

There may be some cases where we want the compiler to changethe ldquotyperdquo of our dataThis is known as ldquocastingrdquo the variable It really is changing thevalue of the variable to the desired type

Functional notationintVar = int(floatVar)

Prefix notationintVar = (int) floatVar

Keyword notationintVar = static castltintgt(floatVar)

Keyword notation is gaining popularity because it is easy to locatein multiple files

3037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What are the mechanics behind ldquocastingrdquo values

There are only two cases

If there is only one data type involved

Trivial case nothing happens

If there is more than one data type involved

Each data type is promoted to the next higher data typeuntil we have a trivial caseOrder of data type promotion int unsigned int long

float double long double

Casting also happens behind the scenes with conditionals Bestadvice is to compare like types

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

1737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Same image

Image from [2]

1837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Example of a ldquoswitchrdquo statement

cin gtgt letter gtgt first gtgt second

switch (letter)

case rsquoArsquo

answer = (first + second)

cout ltlt first ltlt + ltlt second

ltlt is ltlt answer ltlt endl

break

case rsquoSrsquo

answer = (first - second)

cout ltlt first ltlt - ltlt second

ltlt is ltlt answer ltlt endl

break

1937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

More details about the switch statement

The value ofIntegralExpression (of charshort int long or enumtype) determines whichbranch is executed

Case labels are constantintegral expressions

Several case labels canprecede a statement

Control branches to thestatement following thecase label that matches the

value of IntegralExpression

Control proceeds throughall remaining statementsincluding the defaultunless redirected with break

If no case label matches thevalue of IntegralExpressioncontrol branches to thedefault label if present

Otherwise control passes tothe statement following theentire switch statement

Forgetting to use break can cause logical errors

2037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Misc things about break and continue statements

A break statement can beused in switch or any ofthe 3 looping structures

It causes an immediateexit from the currentstructure

If used in a nestedstructure it only exitsthe current structure

A continue statement canonly be used in a loopingstructure

It terminates the currentiteration but not theentire loopIn a ldquoforrdquo loop theupdate is still doneIn a ldquodo ndash whilerdquo theexit condition is tested

Indiscriminate use of break and continue can lead to confusingcode

2137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

C++ operators we will know and love

There are a lot of declaredoperators in C++ Over the nextfew months will will learn aboutthe ones in red and possibly theones in green

Image from [1]

2237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [1]

2337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Specialized C++ operators

What do these expressions do and why

Interesting expressions232 (alpha + beta)delta = 2 12

Confusing expressions

int1 = 14 int2 =++int1

int1 = 14 int2 =int1++

When in doubt fire up CodeBlocks and test them out

2837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

Bit operators

What do these fragments produce and why

When in doubt fire up CodeBlocks and test them out

2937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What if we donrsquot like the type of our variable

There may be some cases where we want the compiler to changethe ldquotyperdquo of our dataThis is known as ldquocastingrdquo the variable It really is changing thevalue of the variable to the desired type

Functional notationintVar = int(floatVar)

Prefix notationintVar = (int) floatVar

Keyword notationintVar = static castltintgt(floatVar)

Keyword notation is gaining popularity because it is easy to locatein multiple files

3037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What are the mechanics behind ldquocastingrdquo values

There are only two cases

If there is only one data type involved

Trivial case nothing happens

If there is more than one data type involved

Each data type is promoted to the next higher data typeuntil we have a trivial caseOrder of data type promotion int unsigned int long

float double long double

Casting also happens behind the scenes with conditionals Bestadvice is to compare like types

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

1837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Example of a ldquoswitchrdquo statement

cin gtgt letter gtgt first gtgt second

switch (letter)

case rsquoArsquo

answer = (first + second)

cout ltlt first ltlt + ltlt second

ltlt is ltlt answer ltlt endl

break

case rsquoSrsquo

answer = (first - second)

cout ltlt first ltlt - ltlt second

ltlt is ltlt answer ltlt endl

break

1937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

More details about the switch statement

The value ofIntegralExpression (of charshort int long or enumtype) determines whichbranch is executed

Case labels are constantintegral expressions

Several case labels canprecede a statement

Control branches to thestatement following thecase label that matches the

value of IntegralExpression

Control proceeds throughall remaining statementsincluding the defaultunless redirected with break

If no case label matches thevalue of IntegralExpressioncontrol branches to thedefault label if present

Otherwise control passes tothe statement following theentire switch statement

Forgetting to use break can cause logical errors

2037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Misc things about break and continue statements

A break statement can beused in switch or any ofthe 3 looping structures

It causes an immediateexit from the currentstructure

If used in a nestedstructure it only exitsthe current structure

A continue statement canonly be used in a loopingstructure

It terminates the currentiteration but not theentire loopIn a ldquoforrdquo loop theupdate is still doneIn a ldquodo ndash whilerdquo theexit condition is tested

Indiscriminate use of break and continue can lead to confusingcode

2137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

C++ operators we will know and love

There are a lot of declaredoperators in C++ Over the nextfew months will will learn aboutthe ones in red and possibly theones in green

Image from [1]

2237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [1]

2337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Specialized C++ operators

What do these expressions do and why

Interesting expressions232 (alpha + beta)delta = 2 12

Confusing expressions

int1 = 14 int2 =++int1

int1 = 14 int2 =int1++

When in doubt fire up CodeBlocks and test them out

2837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

Bit operators

What do these fragments produce and why

When in doubt fire up CodeBlocks and test them out

2937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What if we donrsquot like the type of our variable

There may be some cases where we want the compiler to changethe ldquotyperdquo of our dataThis is known as ldquocastingrdquo the variable It really is changing thevalue of the variable to the desired type

Functional notationintVar = int(floatVar)

Prefix notationintVar = (int) floatVar

Keyword notationintVar = static castltintgt(floatVar)

Keyword notation is gaining popularity because it is easy to locatein multiple files

3037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What are the mechanics behind ldquocastingrdquo values

There are only two cases

If there is only one data type involved

Trivial case nothing happens

If there is more than one data type involved

Each data type is promoted to the next higher data typeuntil we have a trivial caseOrder of data type promotion int unsigned int long

float double long double

Casting also happens behind the scenes with conditionals Bestadvice is to compare like types

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

1937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

More details about the switch statement

The value ofIntegralExpression (of charshort int long or enumtype) determines whichbranch is executed

Case labels are constantintegral expressions

Several case labels canprecede a statement

Control branches to thestatement following thecase label that matches the

value of IntegralExpression

Control proceeds throughall remaining statementsincluding the defaultunless redirected with break

If no case label matches thevalue of IntegralExpressioncontrol branches to thedefault label if present

Otherwise control passes tothe statement following theentire switch statement

Forgetting to use break can cause logical errors

2037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Misc things about break and continue statements

A break statement can beused in switch or any ofthe 3 looping structures

It causes an immediateexit from the currentstructure

If used in a nestedstructure it only exitsthe current structure

A continue statement canonly be used in a loopingstructure

It terminates the currentiteration but not theentire loopIn a ldquoforrdquo loop theupdate is still doneIn a ldquodo ndash whilerdquo theexit condition is tested

Indiscriminate use of break and continue can lead to confusingcode

2137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

C++ operators we will know and love

There are a lot of declaredoperators in C++ Over the nextfew months will will learn aboutthe ones in red and possibly theones in green

Image from [1]

2237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [1]

2337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Specialized C++ operators

What do these expressions do and why

Interesting expressions232 (alpha + beta)delta = 2 12

Confusing expressions

int1 = 14 int2 =++int1

int1 = 14 int2 =int1++

When in doubt fire up CodeBlocks and test them out

2837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

Bit operators

What do these fragments produce and why

When in doubt fire up CodeBlocks and test them out

2937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What if we donrsquot like the type of our variable

There may be some cases where we want the compiler to changethe ldquotyperdquo of our dataThis is known as ldquocastingrdquo the variable It really is changing thevalue of the variable to the desired type

Functional notationintVar = int(floatVar)

Prefix notationintVar = (int) floatVar

Keyword notationintVar = static castltintgt(floatVar)

Keyword notation is gaining popularity because it is easy to locatein multiple files

3037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What are the mechanics behind ldquocastingrdquo values

There are only two cases

If there is only one data type involved

Trivial case nothing happens

If there is more than one data type involved

Each data type is promoted to the next higher data typeuntil we have a trivial caseOrder of data type promotion int unsigned int long

float double long double

Casting also happens behind the scenes with conditionals Bestadvice is to compare like types

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

2037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Things from the past

Misc things about break and continue statements

A break statement can beused in switch or any ofthe 3 looping structures

It causes an immediateexit from the currentstructure

If used in a nestedstructure it only exitsthe current structure

A continue statement canonly be used in a loopingstructure

It terminates the currentiteration but not theentire loopIn a ldquoforrdquo loop theupdate is still doneIn a ldquodo ndash whilerdquo theexit condition is tested

Indiscriminate use of break and continue can lead to confusingcode

2137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

C++ operators we will know and love

There are a lot of declaredoperators in C++ Over the nextfew months will will learn aboutthe ones in red and possibly theones in green

Image from [1]

2237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [1]

2337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Specialized C++ operators

What do these expressions do and why

Interesting expressions232 (alpha + beta)delta = 2 12

Confusing expressions

int1 = 14 int2 =++int1

int1 = 14 int2 =int1++

When in doubt fire up CodeBlocks and test them out

2837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

Bit operators

What do these fragments produce and why

When in doubt fire up CodeBlocks and test them out

2937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What if we donrsquot like the type of our variable

There may be some cases where we want the compiler to changethe ldquotyperdquo of our dataThis is known as ldquocastingrdquo the variable It really is changing thevalue of the variable to the desired type

Functional notationintVar = int(floatVar)

Prefix notationintVar = (int) floatVar

Keyword notationintVar = static castltintgt(floatVar)

Keyword notation is gaining popularity because it is easy to locatein multiple files

3037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What are the mechanics behind ldquocastingrdquo values

There are only two cases

If there is only one data type involved

Trivial case nothing happens

If there is more than one data type involved

Each data type is promoted to the next higher data typeuntil we have a trivial caseOrder of data type promotion int unsigned int long

float double long double

Casting also happens behind the scenes with conditionals Bestadvice is to compare like types

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

2137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

C++ operators we will know and love

There are a lot of declaredoperators in C++ Over the nextfew months will will learn aboutthe ones in red and possibly theones in green

Image from [1]

2237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [1]

2337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Specialized C++ operators

What do these expressions do and why

Interesting expressions232 (alpha + beta)delta = 2 12

Confusing expressions

int1 = 14 int2 =++int1

int1 = 14 int2 =int1++

When in doubt fire up CodeBlocks and test them out

2837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

Bit operators

What do these fragments produce and why

When in doubt fire up CodeBlocks and test them out

2937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What if we donrsquot like the type of our variable

There may be some cases where we want the compiler to changethe ldquotyperdquo of our dataThis is known as ldquocastingrdquo the variable It really is changing thevalue of the variable to the desired type

Functional notationintVar = int(floatVar)

Prefix notationintVar = (int) floatVar

Keyword notationintVar = static castltintgt(floatVar)

Keyword notation is gaining popularity because it is easy to locatein multiple files

3037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What are the mechanics behind ldquocastingrdquo values

There are only two cases

If there is only one data type involved

Trivial case nothing happens

If there is more than one data type involved

Each data type is promoted to the next higher data typeuntil we have a trivial caseOrder of data type promotion int unsigned int long

float double long double

Casting also happens behind the scenes with conditionals Bestadvice is to compare like types

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

2237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [1]

2337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Specialized C++ operators

What do these expressions do and why

Interesting expressions232 (alpha + beta)delta = 2 12

Confusing expressions

int1 = 14 int2 =++int1

int1 = 14 int2 =int1++

When in doubt fire up CodeBlocks and test them out

2837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

Bit operators

What do these fragments produce and why

When in doubt fire up CodeBlocks and test them out

2937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What if we donrsquot like the type of our variable

There may be some cases where we want the compiler to changethe ldquotyperdquo of our dataThis is known as ldquocastingrdquo the variable It really is changing thevalue of the variable to the desired type

Functional notationintVar = int(floatVar)

Prefix notationintVar = (int) floatVar

Keyword notationintVar = static castltintgt(floatVar)

Keyword notation is gaining popularity because it is easy to locatein multiple files

3037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What are the mechanics behind ldquocastingrdquo values

There are only two cases

If there is only one data type involved

Trivial case nothing happens

If there is more than one data type involved

Each data type is promoted to the next higher data typeuntil we have a trivial caseOrder of data type promotion int unsigned int long

float double long double

Casting also happens behind the scenes with conditionals Bestadvice is to compare like types

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

2337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Specialized C++ operators

What do these expressions do and why

Interesting expressions232 (alpha + beta)delta = 2 12

Confusing expressions

int1 = 14 int2 =++int1

int1 = 14 int2 =int1++

When in doubt fire up CodeBlocks and test them out

2837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

Bit operators

What do these fragments produce and why

When in doubt fire up CodeBlocks and test them out

2937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What if we donrsquot like the type of our variable

There may be some cases where we want the compiler to changethe ldquotyperdquo of our dataThis is known as ldquocastingrdquo the variable It really is changing thevalue of the variable to the desired type

Functional notationintVar = int(floatVar)

Prefix notationintVar = (int) floatVar

Keyword notationintVar = static castltintgt(floatVar)

Keyword notation is gaining popularity because it is easy to locatein multiple files

3037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What are the mechanics behind ldquocastingrdquo values

There are only two cases

If there is only one data type involved

Trivial case nothing happens

If there is more than one data type involved

Each data type is promoted to the next higher data typeuntil we have a trivial caseOrder of data type promotion int unsigned int long

float double long double

Casting also happens behind the scenes with conditionals Bestadvice is to compare like types

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

2437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Specialized C++ operators

What do these expressions do and why

Interesting expressions232 (alpha + beta)delta = 2 12

Confusing expressions

int1 = 14 int2 =++int1

int1 = 14 int2 =int1++

When in doubt fire up CodeBlocks and test them out

2837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

Bit operators

What do these fragments produce and why

When in doubt fire up CodeBlocks and test them out

2937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What if we donrsquot like the type of our variable

There may be some cases where we want the compiler to changethe ldquotyperdquo of our dataThis is known as ldquocastingrdquo the variable It really is changing thevalue of the variable to the desired type

Functional notationintVar = int(floatVar)

Prefix notationintVar = (int) floatVar

Keyword notationintVar = static castltintgt(floatVar)

Keyword notation is gaining popularity because it is easy to locatein multiple files

3037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What are the mechanics behind ldquocastingrdquo values

There are only two cases

If there is only one data type involved

Trivial case nothing happens

If there is more than one data type involved

Each data type is promoted to the next higher data typeuntil we have a trivial caseOrder of data type promotion int unsigned int long

float double long double

Casting also happens behind the scenes with conditionals Bestadvice is to compare like types

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

2537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

With so many operators which has precedence

Not all operations are left toright Precedence can be affectedby using parenthesis

Image from [3]

2637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Specialized C++ operators

What do these expressions do and why

Interesting expressions232 (alpha + beta)delta = 2 12

Confusing expressions

int1 = 14 int2 =++int1

int1 = 14 int2 =int1++

When in doubt fire up CodeBlocks and test them out

2837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

Bit operators

What do these fragments produce and why

When in doubt fire up CodeBlocks and test them out

2937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What if we donrsquot like the type of our variable

There may be some cases where we want the compiler to changethe ldquotyperdquo of our dataThis is known as ldquocastingrdquo the variable It really is changing thevalue of the variable to the desired type

Functional notationintVar = int(floatVar)

Prefix notationintVar = (int) floatVar

Keyword notationintVar = static castltintgt(floatVar)

Keyword notation is gaining popularity because it is easy to locatein multiple files

3037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What are the mechanics behind ldquocastingrdquo values

There are only two cases

If there is only one data type involved

Trivial case nothing happens

If there is more than one data type involved

Each data type is promoted to the next higher data typeuntil we have a trivial caseOrder of data type promotion int unsigned int long

float double long double

Casting also happens behind the scenes with conditionals Bestadvice is to compare like types

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

2637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Same image

Image from [3]

2737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Specialized C++ operators

What do these expressions do and why

Interesting expressions232 (alpha + beta)delta = 2 12

Confusing expressions

int1 = 14 int2 =++int1

int1 = 14 int2 =int1++

When in doubt fire up CodeBlocks and test them out

2837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

Bit operators

What do these fragments produce and why

When in doubt fire up CodeBlocks and test them out

2937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What if we donrsquot like the type of our variable

There may be some cases where we want the compiler to changethe ldquotyperdquo of our dataThis is known as ldquocastingrdquo the variable It really is changing thevalue of the variable to the desired type

Functional notationintVar = int(floatVar)

Prefix notationintVar = (int) floatVar

Keyword notationintVar = static castltintgt(floatVar)

Keyword notation is gaining popularity because it is easy to locatein multiple files

3037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What are the mechanics behind ldquocastingrdquo values

There are only two cases

If there is only one data type involved

Trivial case nothing happens

If there is more than one data type involved

Each data type is promoted to the next higher data typeuntil we have a trivial caseOrder of data type promotion int unsigned int long

float double long double

Casting also happens behind the scenes with conditionals Bestadvice is to compare like types

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

2737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

More about C++ operators

Specialized C++ operators

What do these expressions do and why

Interesting expressions232 (alpha + beta)delta = 2 12

Confusing expressions

int1 = 14 int2 =++int1

int1 = 14 int2 =int1++

When in doubt fire up CodeBlocks and test them out

2837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

Bit operators

What do these fragments produce and why

When in doubt fire up CodeBlocks and test them out

2937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What if we donrsquot like the type of our variable

There may be some cases where we want the compiler to changethe ldquotyperdquo of our dataThis is known as ldquocastingrdquo the variable It really is changing thevalue of the variable to the desired type

Functional notationintVar = int(floatVar)

Prefix notationintVar = (int) floatVar

Keyword notationintVar = static castltintgt(floatVar)

Keyword notation is gaining popularity because it is easy to locatein multiple files

3037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What are the mechanics behind ldquocastingrdquo values

There are only two cases

If there is only one data type involved

Trivial case nothing happens

If there is more than one data type involved

Each data type is promoted to the next higher data typeuntil we have a trivial caseOrder of data type promotion int unsigned int long

float double long double

Casting also happens behind the scenes with conditionals Bestadvice is to compare like types

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

2837

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

Bit operators

What do these fragments produce and why

When in doubt fire up CodeBlocks and test them out

2937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What if we donrsquot like the type of our variable

There may be some cases where we want the compiler to changethe ldquotyperdquo of our dataThis is known as ldquocastingrdquo the variable It really is changing thevalue of the variable to the desired type

Functional notationintVar = int(floatVar)

Prefix notationintVar = (int) floatVar

Keyword notationintVar = static castltintgt(floatVar)

Keyword notation is gaining popularity because it is easy to locatein multiple files

3037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What are the mechanics behind ldquocastingrdquo values

There are only two cases

If there is only one data type involved

Trivial case nothing happens

If there is more than one data type involved

Each data type is promoted to the next higher data typeuntil we have a trivial caseOrder of data type promotion int unsigned int long

float double long double

Casting also happens behind the scenes with conditionals Bestadvice is to compare like types

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

2937

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What if we donrsquot like the type of our variable

There may be some cases where we want the compiler to changethe ldquotyperdquo of our dataThis is known as ldquocastingrdquo the variable It really is changing thevalue of the variable to the desired type

Functional notationintVar = int(floatVar)

Prefix notationintVar = (int) floatVar

Keyword notationintVar = static castltintgt(floatVar)

Keyword notation is gaining popularity because it is easy to locatein multiple files

3037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What are the mechanics behind ldquocastingrdquo values

There are only two cases

If there is only one data type involved

Trivial case nothing happens

If there is more than one data type involved

Each data type is promoted to the next higher data typeuntil we have a trivial caseOrder of data type promotion int unsigned int long

float double long double

Casting also happens behind the scenes with conditionals Bestadvice is to compare like types

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

3037

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

What are the mechanics behind ldquocastingrdquo values

There are only two cases

If there is only one data type involved

Trivial case nothing happens

If there is more than one data type involved

Each data type is promoted to the next higher data typeuntil we have a trivial caseOrder of data type promotion int unsigned int long

float double long double

Casting also happens behind the scenes with conditionals Bestadvice is to compare like types

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

3137

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

fragile

A special C++ operator

This type of logic happens a lot

if (someConditional)

c = something

else

c = somethingElse

If fact it is so common in the CC++ world that it was added tothe language It looks like this

c = (someConditional) something somethingElse

Reduces likelihood of typing errors

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

3237

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Break time

Take about 10 minutes

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

3337

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Practice exercises

Programs to load into CodeBlocks and get running

1 ifcpp (look at and understand how nested sequential ldquoifsrdquowork)

2 switchcpp (expand the program to print the first stanza whena 0 is entered)

3 switchescpp (expand to support multiple case labels orsomething else)

Others if you have time

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

3437

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Q amp A time

ldquorsquoThe Answer to the GreatQuestion Of Life the Universeand Everything is forty-tworsquo said DeepThought with infinite majestyand calmrdquoDouglas Adams TheHitchhikerrsquos Guide to theGalaxy

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

3537

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

What have we covered

Returned and discussed test 01Covered looping statements indifferent formsTalked about low level C++operatorsTalked about changing the type ofvariables (casting)Chapter 7 homework before class

Next time Chapter 8

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

3637

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

References I

[1] Richard Smith et al Working draft standard for programminglanguage c++ ISOIEC JTC1SC22WG21 document N4296 (2015)

[2] Sylvia Sorkin Programming and problem solving with c++Teacher Resource Jones and Barlett Learning 2014

[3] C++ Staff C++ operator precedencehttpencppreferencecomwcpplanguage

operator_precedence 2016

3737

Test Results Schedule Miscellanea Control Structs Addrsquol Operrsquos Break Hands on Q amp A Conclusion References Files

Files of interest

1 ifcpp (just to start)

2 switchcpp (to expand)

3 switchescpp (to expand)

4 Programming assignment 003

ifcpp

include lt iostream gt
using namespace std

int main ()


int inputInt

cout ltlt Enter a 2 or 4 or 6

cin gtgt inputInt

cout ltlt You entered ltlt inputInt ltlt endl

cout ltlt Excerpts from Robert Burns To A Mouse On Turning Her Up In Her Nest With The Plough ltlt endl

if ( inputInt == 2 )

cout ltlt O what a panics in thy breastie

else

if ( inputInt == 4 )

cout ltlt Wi bickering brattle

else

if ( inputInt == 6 )

cout ltlt Wi murdring pattle

else
cout ltlt Youre messing with me

cout ltlt endl
return 0



CSC-201 Fall 2016Assignment 3 File Based Address Book

Due Oct 4 2016

Dr Chuck Cartledge

September 21 2016 at 856am

Contents

1 Explanation 1

2 Assignment 1

3 What to submit 3

A Sample files 3

1 Explanation

You will be creating an address book for an absent minded professor This address book willserve as a basis for later programming assignments

The professor has a spotty memory and only remembers parts of things Things likefirst name middle name last name telephone numbers and addresses He remembers apart of each of these things but not the whole thing

He needs a program that will read a comma separated file (where each line in the filecontains all the information he tracks) and then searches whichever selected field he thinkshe remembers for the text he enters

The program needs to print out any and all matches from the address book He hasstarted the program and needs you to finish it

2 Assignment

These are the program requirements

1 Modify the attached interactive program to read the contents of the file

addressBooktsv

The file is attached and contains three silly contacts

2 Modify the program to

(a) Allow the professor to search any field Using

A to search the address field

P to search the phone number field

M to search the middle name field

L to search the last name field

(He got the first name search pretty much done)

(b) Allow the professor to enter upper or lower case command letters

3 The program shall print to standard out See the files section (see Section A) for allfiles Remember your output must go to standard out

4 The program should be properly documented (check the index for page references towhat constitutes good documentation)

Because the professor is basically lazy he will be using IO redirection to test the pro-gram The redirection will look like this

yourCompiledProgram lt addressBookcntrl 1gtnul 2gt resultFile

diff resutltFile goldenFile

It is the results of the diff command that will determine your grade

2

One of the common things about most modern operating systems (OSs) is their use of acommon set of values for file descriptors File descriptors are used by the OS as indices intoa list of queues for processing IO When an application wants to do any IO the applicationgets a file descriptor from the OS and then uses that file descriptor as needed The OS isresponsible for ensuring that the operation goes according to the applicationrsquos direction Itis possible that the OS will not complete an action if the application crashes or does notcleanly end its use of the file descriptorA user can access the preset OS file descriptors outside the application Here is a list ofnormal preset file descriptors

Name Number unistdh stdioh iostreamStandard input 0 STDIN FILENO stdin cinStandard output 1 STDOUT FILENO stdout coutStandard error 2 STDERR FILENO stderr cerr

About file descriptors

Sometimes yoursquoll neither want nor need to save the output from a program Essentiallyyoursquoll want to throw it away because it has no value Most operating systems (OSs) havea special place or syntax for ldquothrowing things awayrdquo An OS supports capturing outputfrom Standard Output Standard Error file descriptors and then redirecting those outputs tosomewhereHere are the special places where output can be redirected to and then lost by the OS

OS PlaceWindows nulnix devnull

About throwing things away

3 What to submit

The C++ source code that meets the assignment requirements

A Sample files

This is a sample input files

bull addressBookcntrl

3

FElseFFirstp12FSomeFhopesQ

1 Modify the attached interactive program to read the contents of the file

addressBooktsv

The file is attached and contains three silly contacts

2 Modify the program to

(a) Allow the professor to search any field Using

A to search the address field

P to search the phone number field

M to search the middle name field

L to search the last name field

(He got the first name search pretty much done)

(b) Allow the professor to enter upper or lower case command letters

3 The program shall print to standard out See the files section (see Section A) for allfiles Remember your output must go to standard out

4 The program should be properly documented (check the index for page references towhat constitutes good documentation)

Because the professor is basically lazy he will be using IO redirection to test the pro-gram The redirection will look like this

yourCompiledProgram lt addressBookcntrl 1gtnul 2gt resultFile

diff resutltFile goldenFile

It is the results of the diff command that will determine your grade

2

One of the common things about most modern operating systems (OSs) is their use of acommon set of values for file descriptors File descriptors are used by the OS as indices intoa list of queues for processing IO When an application wants to do any IO the applicationgets a file descriptor from the OS and then uses that file descriptor as needed The OS isresponsible for ensuring that the operation goes according to the applicationrsquos direction Itis possible that the OS will not complete an action if the application crashes or does notcleanly end its use of the file descriptorA user can access the preset OS file descriptors outside the application Here is a list ofnormal preset file descriptors

Name Number unistdh stdioh iostreamStandard input 0 STDIN FILENO stdin cinStandard output 1 STDOUT FILENO stdout coutStandard error 2 STDERR FILENO stderr cerr

About file descriptors

Sometimes yoursquoll neither want nor need to save the output from a program Essentiallyyoursquoll want to throw it away because it has no value Most operating systems (OSs) havea special place or syntax for ldquothrowing things awayrdquo An OS supports capturing outputfrom Standard Output Standard Error file descriptors and then redirecting those outputs tosomewhereHere are the special places where output can be redirected to and then lost by the OS

OS PlaceWindows nulnix devnull

About throwing things away

3 What to submit

The C++ source code that meets the assignment requirements

A Sample files

This is a sample input files

bull addressBookcntrl

3

FElseFFirstp12FSomeFhopesQ

One of the common things about most modern operating systems (OSs) is their use of acommon set of values for file descriptors File descriptors are used by the OS as indices intoa list of queues for processing IO When an application wants to do any IO the applicationgets a file descriptor from the OS and then uses that file descriptor as needed The OS isresponsible for ensuring that the operation goes according to the applicationrsquos direction Itis possible that the OS will not complete an action if the application crashes or does notcleanly end its use of the file descriptorA user can access the preset OS file descriptors outside the application Here is a list ofnormal preset file descriptors

Name Number unistdh stdioh iostreamStandard input 0 STDIN FILENO stdin cinStandard output 1 STDOUT FILENO stdout coutStandard error 2 STDERR FILENO stderr cerr

About file descriptors

Sometimes yoursquoll neither want nor need to save the output from a program Essentiallyyoursquoll want to throw it away because it has no value Most operating systems (OSs) havea special place or syntax for ldquothrowing things awayrdquo An OS supports capturing outputfrom Standard Output Standard Error file descriptors and then redirecting those outputs tosomewhereHere are the special places where output can be redirected to and then lost by the OS

OS PlaceWindows nulnix devnull

About throwing things away

3 What to submit

The C++ source code that meets the assignment requirements

A Sample files

This is a sample input files

bull addressBookcntrl

3

FElseFFirstp12FSomeFhopesQ

bull addressBooktsv

bull readAddressBook01cpp

4

First NameMiddle NameLast Name(123)456-78905225 Figueroa Mountain Rd Los Olivos CA 93441Someone elseElizaDreams789-123-4567Slaughterville OKSome closeTo ElizaDreams789-123-4567Tulsa OK