Do..While Loop

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:

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


    
        #include<stdio.h>
        #include<stdlib.h>
        
            int main ()
        {
            char c;
            int choice,dummy;
            do{
            printf("\n1. Print Hello\n2. Print Hello WOrld\n3. Exit\n");
            scanf("%d",&choice);
            
            switch(choice)
            {
                case 1 :
                printf("Hello");
                break;
                case 2:
                printf("world");
                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');
        }
    



do while example

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

    
        #include<stdio.h>
        
        int main(){
            int i=1;
            do{
                printf("%d \n",i);
                i++;
            }while(i<=10);

            return 0;
        }
    


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

    
        #include<stdio.h>

        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;
        }
    


Infinitive do while loop

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

    
        do{
             //statement
        }while(1);