Puzzle 22 – Solution

This is a pretty classic puzzle with a pretty classic solution. The program below swaps two numbers without using a temporary variable.

package com.twister;
import java.util.Scanner;

public class Swap{

public static void swap(int a,int b){
    System.out.println("Numbers before change are "
            + a + " and " + b);
    a = a + b;
    b = a - b;
    a = a - b;
    System.out.println("Numbers after change are "
            + a + " and " + b);
}

public static void main(String args[]){
    swap(new Scanner(System.in).nextInt(),
        new Scanner(System.in).nextInt());
}
}

This program works for all values of integer even if we overflow them. Don’t believe me – go ahead and give it a try!!

Congrats to
1. Behive
for getting the right solution.