Java Program to Swap Two Numbers
Without Temporary Variables

Last Updated: 13 August, 2022

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On this tutorial page we are going to learn how to write a Java program to swap two numbers without using a temporary variable.

We can swap two numbers without a temporary variable as follows :

num1 = num1 + num2;
num2 = num1 – num2;
num1 = num1 – num2 ;

Here, we first add num1 and num2 values and store the result in the num2 variable, then subtract num1 from num2 and store the result in the num2, and finally subtract num1 from num2 and store the result in the num1.

Let's see the given examples below:

Program 1: Swap two numbers without a temporary variable in Java

public class SwapTwoNumbers { public static void main(String[] args) { int num1 = 10; // First Number int num2 = 20; // Second Number System.out.println("Before swapping numbers ---"); System.out.println("First number: " + num1); System.out.println("Second number: " + num2); // Swapping Numbers num1 = num1 + num2; num2 = num1 - num2; num1 = num1 - num2; System.out.println("\nAfter swapping numbers ---"); System.out.println("First number = " + num1); System.out.println("Second number = " + num2); } }

Output

Before swapping numbers ---
First number: 10
Second number: 20

After swapping numbers ---
First number = 20
Second number = 10

Program 2: Swap two numbers without a temporary variable in Java with user input

import java.util.Scanner; public class SwapTwoNumbers { public static void main(String[] args) { Scanner scanner = new Scanner(System.in); System.out.print("Enter First Number: "); int num1 = scanner.nextInt(); System.out.print("Enter Second Number: "); int num2 = scanner.nextInt(); scanner.close(); // Swapping Numbers num1 = num1 + num2; num2 = num1 - num2; num1 = num1 - num2; System.out.println("\nAfter swapping numbers ---"); System.out.println("First number = " + num1); System.out.println("Second number = " + num2); } }

Output

Enter First Number: 2000
Enter Second Number: 4000

After swapping numbers ---
First number = 4000
Second number = 2000