Java Program to Swap Two Numbers

Write a Java Program to Swap Two Numbers using a temporary variable and without a temporary or third variable. For this swap of two numbers program purpose, we are going to use Arithmetic Operators and Bitwise Operators.

Java Program to Swap Two Numbers using Temp Variable

This program allows the user to enter two integer values. By using the third variable and the assignment operator, this example Swaps those two numbers.

import java.util.Scanner;

public class Example {	
	
	private static Scanner sc;	
	 
	public static void main(String[] args) 
	{	
		int a, b, temp;
		sc = new Scanner(System.in);
		
		System.out.print(" Please Enter the First : ");
		a = sc.nextInt();	
		
		System.out.print(" Please Enter the Second : ");
		b = sc.nextInt();	
		
		System.out.println("\n Before : a =  " + a + " and b =  " + b);
		
		temp = a;
		a = b;
		b = temp;
		
		System.out.println("\n After :  a =  " + a + " and b =  " + b);
	}
}

In the above Program to Swap Two Numbers example, we assigned a = 10 and b = 25.

Temp = a – it means assigning a value to the Temp variable.
Temp = 10

a = b – assigning b value to the variable a.
a = 25

b = Temp – assigning Temp value to b.
b = 6

Java Program to Swap Two Numbers without Using Temp Variable

In this example, Instead of using the temp or third variable to swap two numbers, we are going to use Arithmetic Operators.

import java.util.Scanner;

public class Example2 {
	private static Scanner sc;
	public static void main(String[] args) 
	{
		int a, b;
		sc = new Scanner(System.in);
		
		System.out.print(" Please Enter the First value : ");
		a = sc.nextInt();	
		
		System.out.print(" Please Enter the Second value : ");
		b = sc.nextInt();	
		
		System.out.println("\n Before : a =  " + a + " and b =  " + b);
		
		a = a + b;
		b = a - b;
		a = a - b;
		
		System.out.println("\n After :  a =  " + a + " and b =  " + b);
	}
}

Using arithmetic operators result.

User Entered Values are a = 6 and b = 13

a = a + b
a = 6 + 13 = 19

b= a-b = 19 – 13 = 6

a = a-b = 19 – 6 = 13
Final Values of the 2 numbers: a = 13 and b = 6

NOTE: We can interchange 2 numbers using the multiplication and division approach. But it may produce strange values if we work with larger integer values or if any of them is 0.

Java Program to Swap Two Numbers using Bitwise OR Operator

In this example, Instead of using the temp variable, we will use Bitwise Operators to swap 2 numbers.

import java.util.Scanner;

public class Example3 {
	private static Scanner sc;
	public static void main(String[] args) 
	{
		int a, b;
		sc = new Scanner(System.in);
		
		System.out.print(" Please Enter the First value : ");
		a = sc.nextInt();	
		
		System.out.print(" Please Enter the Second value : ");
		b = sc.nextInt();	
		
		System.out.println("\n Before : a =  " + a + " and b =  " + b);
		
		a = a ^ b;
		b = a ^ b;
		a = a ^ b;
		
		System.out.println("\n After :  a =  " + a + " and b =  " + b);
	}
}

Output

Java Program to Swap Two Numbers Using Functions

This program is the same as the first Java example. But we separated the logic and placed it in a separate method.

import java.util.Scanner;

public class Example4 {
	private static Scanner sc;
	public static void main(String[] args) 
	{
		int a, b;
		sc = new Scanner(System.in);
		
		System.out.print(" Please Enter the First value : ");
		a = sc.nextInt();	
		
		System.out.print(" Please Enter the Second value : ");
		b = sc.nextInt();	
		
		System.out.println("\n Before : a =  " + a + " and b =  " + b);
		swfunc(a, b);
		
	}
	
	public static void swfunc(int a, int b)
	{
		int temp;
		
		temp = a;
		a = b;
		b = temp;
		
		System.out.println("\n After :  a =  " + a + " and b =  " + b);
	}
}

 Please Enter the First value : 12
 Please Enter the Second value : 95

 Before : a =  12 and b =  95

 After :  a =  95 and b =  12