do while loop in C

The do while loop is a post tested loop. Using the do-while loop, we can repeat the execution of several parts of the statements. The do-while loop is mainly used in the case where we need to execute the loop at least once. The do-while loop is mostly used in menu-driven programs where the termination condition depends upon the end user.

do while loop syntax

The syntax of the C language do-while loop is given below:

snippet
do{
//code to be executed
}while(condition);

Example 1

snippet
#include<stdio.h>
#include<stdlib.h>
void main ()
{
	char c;
	int choice,dummy;  
	do{
	printf("\n1. Print Hello\n2. Print Javatpoint\n3. Exit\n");
	scanf("%d",&choice);
	switch(choice)
	{
		case 1 : 
		printf("Hello"); 
		break;
		case 2:  
		printf("Javatpoint");
		break;
		case 3:
		exit(0); 
		break;
		default: 
		printf("please enter valid choice"); 	
	}
	printf("do you want to enter more?"); 
	scanf("%d",&dummy);
	scanf("%c",&c);
	}while(c=='y');
}

Output

Output
1. Print Hello 2. Print Javatpoint 3. Exit 1 Hello do you want to enter more? y 1. Print Hello 2. Print Javatpoint 3. Exit 2 Javatpoint do you want to enter more? n

Flowchart of do while loop

flowchart of do while loop in c language

do while example

There is given the simple program of c language do while loop where we are printing the table of 1.

snippet
#include
int main(){  
int i=1;    
do{  
printf("%d \n",i);  
i++;  
}while(i<=10); 
return 0;
}

Output

Output
1 2 3 4 5 6 7 8 9 10

Program to print table for the given number using do while loop

snippet
#include
int main(){  
int i=1,number=0;  
printf("Enter a number: ");  
scanf("%d",&number);  
do{  
printf("%d \n",(number*i));  
i++;  
}while(i<=10);  
return 0;
}

Output

Output
Enter a number: 5 5 10 15 20 25 30 35 40 45 50
Output
Enter a number: 10 10 20 30 40 50 60 70 80 90 100

Infinitive do while loop

The do-while loop will run infinite times if we pass any non-zero value as the conditional expression.

snippet
do{
//statement
}while(1);
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