Homework 4a and 4b

CMSC 104, Section 301, Fall 2002 1 Lecture 17, 11/04/02

Homework 4a and 4b

Topics

• Go over Homework 4aProblems 2.7 - 2.15, Problems 3.11 - 3.13

• Go over Homework 4aProblems 4.5 - 4.8


Homework 4a

2.7 Identify and correct errors:

a. scanf( “d”, value) ;

b. Printf( “The product of %d and %d is %d”\n, x, y ) ;


Homework 4a


c. firstNumber + secondNumber = sumOfNumbers

d. If ( number => largest ) largest == number ;


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e. */ Program to determine the largest of three integers /*

f. Scanf(“%d”, anInteger);


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g. printf( “Remainder of %d divided by %d is\n”, x, y, x % y);

h. If ( x = y );

printf( %d is equal to %d\n”, x, y );


Homework 4a


i. print( “The sum is %d\n,” x + y );

j. Printf( “The value you enter is: %d\n, &value );


Homework 4a

2.8 Fill in the blanks:a) _________ are used to document a program and

improve its readability.b) The function used to print information on the

screen is __________.c) A C statement that makes a decision is ___.d) Calculations are normally performed by

_______________ statements.e) The ____________ function inputs values from

the keyboard.


Homework 4a

2.9 Write a single C statement;

a) Print the message “Enter two numbers.”

b) Assign the product of variables b and c to variable a


Homework 4a

2.9 Write a single C statement;c) State that a program performs a sample

payroll calculation (i.e., use text that helps to document a program).

d) Input three integer values from the keyboard and place these values in integer variables a, b, and c.


Homework 4a

2.10 True or False.

a) C operators are evaluated from left to right.

b) The following are all valid variable names:_under_bar_, m928134, t5, j7, her_sales,

his_account_total, a, b, c, z, z2


Homework 4a

2.10 True or False.

c) The statement printf(“a = 5;”); is a typical example of an assignment statement.

d) A valid C arithmetic expression containing no parentheses is evaluated from left to right.


Homework 4a

2.10 True or False.

e) The following are all invalid variables names: 3g, 87, 67h2, h22, 2h


Homework 4a

2.11 Fill in the blanks.

a) What arithmetic operations are on the same level of precedence as multiplication?

b) When parentheses are nested, which set of parentheses is evaluated first in an arithmetic expression?


Homework 4a

2.11 Fill in the blanks.

c) A location in the computer’s memory that may contain different values at various times throughout the execution of a program is called a ___________.


Homework 4a

2.12 Assume x = 2 and y = 3. Output?

a) printf( “%d”, x);

b) printf( “%d”, x + x);

c) printf( “x=“ );

d) printf( “x=%d”, x);


Homework 4a

2.12 Assume x = 2 and y = 3. Output?e) printf( “%d = %d”, x + y, y + x);

f) z = x + y ;

g) scanf( “%d%d”, &x, &y );

h) /* printf( “x + y = %d”, x + y); */

i) printf( “\n” );


Homework 4a

2.13 Destructive read-in?

a) scanf( “%d%d%d%d%d”, &b,&c,&d,&e,&f);

b) P = I + j + k + 7 ;

c) printf( “Destructive read-in” );

d) printf( “a = 5”);


Homework 4a

2.14 Given y = ax3 + 7 ; Which are correct?

a) y = a * x * x * x + 7 ;

b) y = a * x * x * (x + 7) ;

c) y = (a * x) * x * (x + 7) ;

d) y = (a * x) * x * x + 7 ;

e) y = a * (x * x * x) + 7 ;

f) y = a * x * x * x + 7 ;


Homework 4a

2.15 State the order of evaluation and find x.

a) x = y + 3 * 6 / 2 - 1;


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b) x = 2 % 2 + 2 * 2 - 2 / 2 ;


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c) x = ( 3 * 9 * ( 3 + ( 9 * 3 / ( 3 ) ) ) );


Homework 4a

3.11 Identify and correct errors.

d) while ( y > 0 ) {

printf (“%d\n”, y );

++y;

}


Homework 4a

3.12 Fill in blanks.

a) The solution to any problem involves performing a series of actions in a specific ___________.

b) A synonym for procedure is ___________.

c) A variable that accumulates the sum of several number is a __________.

d) The process of setting certain variables to specific values at the beginning of a program is called ________________.


Homework 4a


e) A special value used to indicate “end of data entry” is called a __________________, a __________________, a __________________, or a __________________ value.


Homework 4a

3.12 Fill in blanks.f) A _________________ is a graphical

representation of an algorithm.g) In a flowchart, the order in which the steps

should be preformed is indicated by _____________________ symbols.

h) The termination symbol indicates the _____________ and ___________ of every algorithm.


Homework 4a


i) Rectangle symbols correspond to calculations that are normally performed by ________________ statements and input/output operations that are normally by calls to the ____________ and _________ standard library functions.

j) The item written inside a decision symbol is called a ________________.


Homework 4a

3.13 Output of this program?#include <stdio.h>int main () { int x = 1, total = 0, y;

while ( x <= 10 ) { y = x * x; printf(“%d\n”, y); total += y; ++x; } printf(“Total is %d\n”, total); return 0;}


Homework 4b


a) for ( x = 100, x >= 1, x++ )

printf( “%d\n”, x );


Homework 4b


c) Input is “100 A” and print the input. scanf( “%d”, &intVal );

charVal = getchar();

printf( “Integer: %d\nCharacter: %c\n”, intVal, charVal );


Homework 4b


d) for ( x = .000001; x <= .0001; x += .000001)

printf( “%.7f\n”, x);


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e) Output the odd integers from 999 to 1.

for ( x = 999; x >= 1; x += 2) printf( “%.d\n”, x);


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f) Output even integers from 2 to 100.

counter = 2;

Do {

if ( counter % 2 == 0)

printf( “%.d\n”, counter);

counter += 2;

} While (counter < 100) ;


Homework 4b


g) Sum from 100 to 150.

for ( x = 100; x <= 150; x ++) ;

total += x;


Homework 4b

4.6 Output?a) for ( x = 2; x <= 13; x += 2) printf( “%d\n”, x);

b) for ( x = 5; x <= 22; x += 7) printf( “%d\n”, x);

c) for ( x = 3; x <= 15; x += 3) printf( “%d\n”, x);


Homework 4b

4.6 Output?

d) for ( x = 1; x <= 5; x += 7)

printf( “%d\n”, x);

e) for ( x = 12; x >= 2; x -= 3)

printf( “%d\n”, x);


Homework 4b

4.7 Write for statements.

a) 1,2,3,4,5,6,7

b) 3,8,13,18,23


Homework 4b

4.7 Write for statements.

c) 20,14,8,2,-4,-10

d) 19,27,35,43,51


Homework 4b

4.8 Output?printf( "Enter two integers in the range 1-20:\n"); scanf("%d%d", &x, &y) ; for ( i = 1; i <= y; i ++) {

for (j = 1; j <= x; j++ ) printf( "@");

printf( "\n"); }


Assignment and Next

• Read Sections 3.9 – 3.10

Next:• Exam 2 on Wednesday, 11/06.• Project 2 due Sudany, 11/10, midnight.

Documents

Homework 4a and 4b