Java Tutorial: The do-while loop in Java

Do-while loop:

• Do- while loop is similar to a while loop except for the fact that it is guaranteed to execute at least once.
• Use a do-while loop when the exact number of iterations is unknown, but you need to execute a code block at least once.
• After executing a part of a program for once, the rest of the code gets executed on the basis of a given boolean condition.
• Syntax :

/* do {

            //code

} while (condition);            //Note this semicolon */

• Example

int i=1;  
do{  
System.out.println(i);  
i++;  
}while(i<=10); 

Difference Between while loop and do-while loop :

• while – checks the condition & executes the code.
• do-while – executes the code at least once and then checks the condition. Because of this reason, the code in the do-while loop executes at least once, even if the condition fails.

Flow control of do-while loop :

Quick Quiz: Write a program to print first n natural numbers using a do-while loop.

Code as described in the video :

public class cwh_22_ch4_do_while {
    public static void main(String[] args) {
//        int a = 0;
//        while(a<5){
//            System.out.println(a);
//            a++;
//        }
        int b = 10;
        do {
            System.out.println(b);
            b++;
        }while(b<5);

        int c = 1;
        do{
            System.out.println(c);
            c++;
        }while(c<=45);

    }
}

**Handwritten Notes: Click to Download

**Ultimate Java Cheatsheet: Click To Download