Lec03_Basic Elements C++

8/13/2019 Lec03_Basic Elements C++

1/28

BASIC ELEMENTSOF

C++


2/28

OBJECTIVES

To be able to use C++

input/outputand formatting

To become familiar with the

C++standard


3/28

Outcome

Know how to write your firstprogram in C++ using basicelements of C++.


4/28

Hello C++!

// This is a C++ program. It prints the sentence:// Welcome to C++ Programming.

#include using namespace std;

int main(){

cout


5/28

Your First Program Explained


6/28

Your First Program Explained

#include- read the file iostreamthat contains the definition for the stream

input/output package.

using namespace std;- all names in theprogram belong to the "standard namespace"


7/28

cout


8/28

New Line \n or endl


int main(){

cout


9/28

Comments

Comments can be written in two styles: Single line:

double can_volume = 0.355; // Liters in a 12-ouncecan

Multiline for longer comments:

/*This program computes the volume (in liters)of a six-pack of soda cans.

*/


10/28

Basic data types in C++Data type C++ keyword Range

Integer int -32768 to 32767

Long integer long -4294967296 to 4294967295

Short integer short -128 to 127

Unsigned integer unsigned 0 to 65535

Character char 0 to 255

Floating point float 6 digits of precision

Double floating point double 12 digits of precision

Example of declaration

float amount; //Declares amount as a floating-point variable

int number; //Declares number as an integer variable

char ch; //Declares ch as a character variable


11/28

C++ operators

Several classes of operators

Arithmetic

Relational

Logical

Assignment


12/28

Arithmetic operators

Seven arithmetic operators in C++ ( E.g. int a = 7, b =2; )

Operators Action

- Substraction

+ Addition

* Multiplication

/ Division

% Modulus division

- - Decrement

+ + Increment

Expression Value

a - b 5a + b 9

a * b 14

a / b 3

a % b 1

a-- 6

b++ 3


13/28

Arithmetic Operators (Integer)


int main(){

// Integers Expression

cout


14/28

Arithmetic Operators (Float)


int main(){

// Floating-point expression

cout


15/28

Arithmetic Operators (Mix)


int main()

{ // Mix expression

cout


16/28

Relational operators

Six relational operators in C++

The results is either TRUE(1)or FALSE (0)

E.g.

if a = 7andb = 5, then a < byields 0and a != byields 1Operator Meaning

< Less than

Greater than

>= Greater than or equal

= = Equal

!= Not equal


17/28

Logical Operators

&&(logicalAND) Returns trueif both conditions are true

||(logical OR)

Returns trueif either of its conditions are true

!(logicalNOT, logical negation) Reverses the truth/falsity of its condition

Returns truewhen its condition is false

Logical operators used as conditions in loops

Expression Resulttrue && false falsetrue || false true!false true


18/28

Assignment Operators

Most commonly used assignment operator is =(e.g. int Q = 5; )

Assignment expression abbreviations

c = c + 3;can be abbreviated as c += 3;using the additionassignment operator

Examples of other assignment operators include:d -= 4 (d = d - 4)

e *= 5 (e = e * 5)f /= 3 (f = f / 3)g %= 9 (g = g % 9)


19/28

Increment and Decrement Operators

Find the value of i and j (Assume i = 1)

int j = ++i // j is 2 , i is 2

int j = i++ // j is 1, I is 2

int j = --i // j is 0, I is 0

int j = i-- //j is 1, I is 0

T C i (C ti )


20/28

Type Conversion (Casting)#include using namespace std;

int main(){

cout


21/28

Allocating Memory with Constants

const doubleCONVERSION = 2.54;

const intNO_OF_STUDENTS = 20;

const charBLANK = ;

const doublePAY_RATE = 15.75;

Constant?A memory location whose content is not

allowed to change during program execution.


22/28

Allocating Memory with Variables

doublesale; intnum1, num2;

charfirst;

stringstr;

Variable?A memory location whose content maychange during program execution.

num1 = 4; num2 = 4*5-11;

sale = 0.02 * 1000;

first = D; str = It is a sunny day.;

i l d i


23/28


int main(){

const intNO_STUD = 20;

stringstr;str = All are good students;

cout


24/28

Input (Read) Statement#include using namespace std;

int main()

{int feet, inches;

cout feet >> inches;cout


25/28

Increment & Decrement Operators#include using namespace std;

int main()

{int num = 0, num2 = 0, tot = 5;

num++;

num2 = num2 + 1;cout


26/28

Preprocessor Directives

#include #include using namespace std;

int main(){

int num;string name;

coutnum;

coutname;

return 0; }


27/28

Lets Try!

Write a program that prompts the user to enter twotest scores and then prints the average test score.(Assume test scores are decimal numbers.)


28/28

Lets Try!

Write a program that converts Fahrenheit degrees toCelsius using the formula :

Celcius = 5/9 * (Fahrenheit 32)

Documents

Lec03_Basic Elements C++