This java code reverse any integer,but i don't understand how it works since rev=0; rev*10 in a while loop shouldn't be zero?

Question

import java.util.Scanner;

public class H {

public static void main(String[] args) {

int no, rev = 0, r;
Scanner s = new Scanner(System.in);
System.out.println("Enter any no.: ");
no = s.nextInt();

while (no > 0) {
r = no % 10;
rev = rev * 10 + r;
no = no / 10;
}
System.out.println("Reverse: " + rev);

}
}

Answer 1

Dessie Bahiru Don't forget that the loop will continue to run while (no > 0)

So even if 'rev = 0' after the first run through the loop, as long as (no > 0) the loop will continue to run

Which means the value of 'rev' could change after each iteration

Edit to your code below isn't perfect, but I find it helps to print each iteration to see the changes, what's going on behind the scenes

Hope that helps 😊

https://code.sololearn.com/cZl46p5S91I9/?ref=app

Answer 2

Write print statement after rev=rev*10+r; or last statement in while loop to look how the values are changing..
by printing variable values...you find it easily.. like
System.out.println(r+" "+rev+" "+no);