do-while in C

do-while in C

A do-while loop is similar to a while loop, except that a do-while loop is execute at least one time.

A do while loop is a control flow statement that executes a block of code at least once, and then repeatedly executes the block, or not, depending on a given condition at the end of the block (in while).

Syntax

do
{
Statements;
........
Increment or Decrements (++ or --)
}
while(condition);

Flow Diagram

When use do..while loop

when we need to repeat the statement block at least one time then use do-while loop. In do-while loop post-checking process will be occur, that is after execution of the statement block condition part will be executed.

In below example you can see in this program i=20 and we check condition i is less than 10, that means condition is false but do..while loop execute once and print Hello world ! at one time.

Example of do..while loop

#include<stdio.h>
#include<conio.h>

void main()
{
int i=20;
do
{
printf("Hello world !");
i++;
}
while(i<10);
getch();
}

Output

Hello world !

Example of do..while loop

#include<stdio.h>
#include<conio.h>

void main()
{
int i;
clrscr();
i=1;
do
{
printf("\n%d",i);
i++;
}
while(i<5);
getch();
}

Output

1
2
3
4

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