For Loop While Loop Do while Loop
Do while loop
syntax:
do
{
statements;
statements;
statements;
}while(condition);
* Do while loop is an exit control loop.
* In the do-while loop the statements of the loop are executed first and then the condition is checked.
* In the do-while loop irrespective of whether the condition is true or false the statements of the loop are executed at least once.
Difference between while loop and do while loop
| while loop | do while loop |
| While(condition) { statements; } | do { statements; }while(condition); |
| While loop is an entry control loop | Do while loop is an exit control loop |
| In while loop the condition is checked first then the statements of the loop are executed | In do while loop the statements of the loop are executed first and then the condition is checked. |
| In while loop if the condition is true then only the control will enter the loop and the statements will be executed. | In do while loop irrespective of whether the condition is true or false the statements of the loop will get executed at least once. |
| i=11; while(i<=10) { printf(“%d\n”,i); i++; } o/p : (blank) | i=11; do { printf(“%d\n”,i); i++; }while(i<=10); o/p:11 |
Examples of do while loop
Question:1
C Program to input for a number, calculate and print its square and add the continue condition?
Sol:
#include <stdio.h>
int main()
{
int a,b;
char ch;
do
{
printf("Enter any no ");
scanf("%d",&a);
b=a*a;
printf("Square = %d\n",b);
printf("Like to cont ... (y/n) ");
fflush(stdin);
scanf("%c",&ch);
}while(ch=='y' || ch=='Y');
return 0;
}
Output:
Enter any no 2
Square = 4
Like to cont … (y/n) y
Enter any no 6
Square = 36
Like to cont … (y/n) y
Enter any no 5
Square = 25
Like to cont … (y/n) n
Question:2
C Program to input for a number, calculate and print its cube and add the continue condition?
Sol:
#include <stdio.h>
int main()
{
int a,b;
char ch;
do
{
printf("Enter any no ");
scanf("%d",&a);
b=a*a*a;
printf("Cube = %d\n",b);
printf("Like to cont ... (y/n) ");
fflush(stdin);
scanf("%c",&ch);
}while(ch=='y' || ch=='Y');
return 0;
}
Output:
Enter any no 2
Cube = 8
Like to cont … (y/n) y
Enter any no 5
Cube = 125
Like to cont … (y/n) y
Enter any no 8
Cube = 512
Like to cont … (y/n) n
Question:3
C Program to input for 2 numbers calculate and print their sum and add the continue condition?
Sol:
#include <stdio.h>
int main()
{
int a,b,c;
char ch;
do
{
printf("Enter 2 nos ");
scanf("%d %d",&a,&b);
c=a+b;
printf("Sum = %d\n",c);
printf("Like to cont ... (y/n) ");
fflush(stdin);
scanf("%c",&ch);
}while(ch=='y' || ch=='Y');
return 0;
}
Output:
Enter 2 nos 10
25
Sum = 35
Like to cont … (y/n) y
Enter 2 nos 23
63
Sum = 86
Like to cont … (y/n) n
Question:4
C Program to input for 3 numbers calculate and print their product and add the continue condition?
Sol:
#include <stdio.h>
int main()
{
int a,b,c,d;
char ch;
do
{
printf("Enter 3 nos ");
scanf("%d %d %d",&a,&b,&c);
d=a*b*c;
printf("Product = %d\n",d);
printf("Like to cont ... (y/n) ");
fflush(stdin);
scanf("%c",&ch);
}while(ch=='y' || ch=='Y');
return 0;
}
Output:
Enter 3 nos 10
20
30
Product = 6000
Like to cont … (y/n) y
Enter 3 nos 2
6
3
Product = 36
Like to cont … (y/n) y
Enter 3 nos 5
6
2
Product = 60
Like to cont … (y/n) n
Question:5
C Program to take input for 3 numbers, check and print the largest number. Add the continue condition?
Sol:
#include <stdio.h>
int main()
{
int a,b,c,m;
char ch;
do
{
printf("Enter 3 nos ");
scanf("%d %d %d",&a,&b,&c);
if(a>b && a>c)
m=a;
else
if(b>c)
m=b;
else
m=c;
printf("Max no = %d\n",m);
printf("Like to cont ... (y/n) ");
fflush(stdin);
scanf("%c",&ch);
}while(ch=='y' || ch=='Y');
return 0;
}
Output:
Enter 3 nos 25
96
3
Max no = 96
Like to cont … (y/n) y
Enter 3 nos 25
87
54
Max no = 87
Like to cont … (y/n) n
