Difference between while & do while loops in C

C  Loop control statement

Loop control statements in C are used to perform looping operations until the given condition is true. Control comes out of the loop statements once condition becomes false.

Types of loop control statements in C:

There are 3 types of loop control statements in C language. They are,

1. for
2. while
3. do-while

 

Example program (For Loop) in C:

#include <stdio.h> int main() { int i; for(i=0;i<10;i++) { printf("%d ",i); } }

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#include <stdio.h>   int main() {   int i;     for(i=0;i<10;i++)   {       printf("%d ",i);   }       }

Output:

0 1 2 3 4 5 6 7 8 9

Example program (while loop) in C:

      In while loop control statement, loop is executed until condition becomes false.

#include <stdio.h> int main() { int i=3; while(i<10) { printf("%d\n",i); i++; } }

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#include <stdio.h>   int main() {   int i=3;     while(i<10)   {       printf("%d\n",i);       i++;   }       }

Output:

3 4 5 6 7 8 9

Example program (do while loop) in C:

      In do..while loop control statement, while loop is executed irrespective of the condition for first time. Then 2^nd time onwards, loop is executed until condition becomes false.

C

#include <stdio.h> int main() { int i=1; do { printf("Value of i is %d\n",i); i++; }while(i<=4 && i>=2); }

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#include <stdio.h>   int main() {   int i=1;     do   {         printf("Value of i is %d\n",i);       i++;   }while(i<=4 && i>=2);       }

Output:

Value of i is 1 Value of i is 2 Value of i is 3 Value of i is 4

Difference between while & do while loops in C:

S.no	while	do while
1	Loop is executed only when condition is true.	Loop is executed for first time irrespective of the condition. After executing while loop for first time, then condition is checked.