1. Chapter 8
The Loops
By:
Mr. Baha Hanene

2. Learning Outcomes In this chapter we will cover learning outcome no. 4
Use the program control structures of Sequences, Selections and Repetitions as well as simple functions to develop C programs to meet specified tasks. L04

3. THE WHILE LOOP Initialization (counter)
THE FORMAT
Initialization (counter)
while (<testing> or <condition>) {
body for the loop (statements)
increment for the counter }
EXAMPLE
count = 0;
while (count < = 10) {
printf (“ \n %i ”, count);
count++; or count=count+1; }

4. THE OUTPUT

5. THE FOR LOOP
THE FORMAT
for (<initialization>; <testing>; <increment>) {
body for the loop (statements) }
EXAMPLE
for (count = 0; count < = 10; count++) {
printf (“ \n %i ”, count); }

6. THE OUTPUT

7. THE DO-WHILE LOOP Initialization (counter) do {
THE FORMAT
Initialization (counter) do {
body for the loop (statements)
increment for the counter
} while (<testing> or <condition>);
EXAMPLE
count = 0; do {
printf (“ \n %i ”, count);
count++; or count=count+1;
} while (count<=10);

8. THE OUTPUT

9. Comparison (While Loop Vs. For Loop)
If we want to display the numbers from 0 to 10 then both loop statements will be as below.
int count = 0;
while ( count < = 10 )
{ printf (“ \n %i ”, count);
count++; }
Initialization
Increment
int count;
for (count = 0; count < = 10; count++) {
printf (“ \n %i ”, count); }

10. A Sample Program
Q: Write a program to display numbers from zero to ten.
#include <stdio.h>
void main() {
int num;
for (num = 0; num < = 10; num++)
printf (“ \n %d ”, num); }

11. THE OUTPUT

12. Q: Change the previous program to prompt the user to enter the last number and then display the numbers from 0 to the last number.
#include <stdio.h>
void main()
{ int num, last ;
printf(“\n Enter The Last Number = ”);
scanf(“%d”, & last);
for (num = 0; num < = last; num++) {
printf (“ \n %d ”, num); }

13. THE OUTPUT

14. Q: Again change the previous program to prompt the user to enter the first & the last number and then display the numbers accordingly.
#include <stdio.h>
void main()
{ int num, first, last ;
printf(“\n Enter The First Number = ”);
scanf(“%d”, & first);
printf(“\n Enter The Last Number = ”);
scanf(“%d”, & last)
for (num = first; num < = last; num++) {
printf (“ \n %d ”, num); }

15. THE OUTPUT

16. Q: Write a program to get three numbers from the user, add them together & print their total & average.

17. THE OUTPUT

18. Q: Write a program to get three numbers from the user, add them together & print their total & average.

19. THE OUTPUT

20. GUESS THE OUTPUT 1) for (a=0; a=5; a++) 3) for (a=1; a<=5; a++)
Which code from the following prints “Hello” 5 times?
1) for (a=0; a=5; a++)
printf(“\n Hello”);
3) for (a=1; a<=5; a++)
2) for (a=0; a==5; a++)
4) for (a=1; a==5; a+=2)
Answer : 3

21. What is the output for the following?
# include <stdio.h> void main() { int i, y, z=0; for (i=5; i<10; i++) { y = ++z; printf(“%d ”,y); }
Output :

22. Q: Write the program to read the salary of ten employees, add them and then display the total & average of all the salaries.

23. THE OUTPUT

24. Q: Write a program to display odd numbers between a range, whereas the range must be input by the user.

25. THE OUTPUT

26. To change the odd number program into even number, the following places we need to change….

27. Q: Write a program to display the odd or even numbers with the count of displayed numbers.

28. THE OUTPUT

29. Q: What is the output for the following program?
j k l
For Loop Start
i = 0
i = 2
i = 4
i = 6
i = 8