Swap Two Numbers: In 5 Different Ways

Program to swap two numbers

Input:
Enter the value of X and Y
num1=10
num2=20
Before swapping: 10    20

Output:
num1=20
num2=10
After swapping: 20    10

Solution:

Language Used: Java

Approach 1: swap two numbers using the third variable

import java.util.Scanner;

public class Swap {

    public static void main(String[] args) {
        // swap two numbers
        Scanner s = new Scanner(System.in) ;

        System.out.println("Enter first number");
        int num1 = s.nextInt() ;

        System.out.println("Enter second number");
        int num2 = s.nextInt() ;

        System.out.println("Before swapping: "+num1+" "+num2);

         logic-1 - swap two numbers using third variable 

        int temp;

        temp = num1; //10 
        num1 = num2; //20
        num2 = temp; //10 

        System.out.println("After swapping: "+num1+" "+ num2);

    }

}

Approach 2: swap two numbers without using a third variable using + and -

import java.util.Scanner;

public class Swap {

    public static void main(String[] args) {
        // swap two numbers
        Scanner s = new Scanner(System.in) ;

        System.out.println("Enter first number");
        int num1 = s.nextInt() ;

        System.out.println("Enter second number");
        int num2 = s.nextInt() ;

        System.out.println("Before swapping: "+num1+" "+num2);

        // logic-2  - swap two numbers without using third variable using + and -

        num1=num1+num2 ;
        num2=num1-num2 ;
        num1=num1-num2 ;   


        System.out.println("After swapping: "+num1+" "+ num2);

    }

}

Approach 3: swap two numbers using * and /

import java.util.Scanner;

public class Swap {

    public static void main(String[] args) {
        // swap two numbers
        Scanner s = new Scanner(System.in) ;

        System.out.println("Enter first number");
        int num1 = s.nextInt() ;

        System.out.println("Enter second number");
        int num2 = s.nextInt() ;

        System.out.println("Before swapping: "+num1+" "+num2);

        //logic - 3 - using * and /

        num1=num1*num2 ;
        num2=num1/num2 ;
        num1=num1/num2 ;    

        System.out.println("After swapping: "+num1+" "+ num2);

    }

}

Approach 4: swap two numbers using bitwise X-OR

import java.util.Scanner;

public class Swap {

    public static void main(String[] args) {
        // swap two numbers
        Scanner s = new Scanner(System.in) ;

        System.out.println("Enter first number");
        int num1 = s.nextInt() ;

        System.out.println("Enter second number");
        int num2 = s.nextInt() ;

        System.out.println("Before swapping: "+num1+" "+num2);


        // logic-4 using bitwise X-OR

        num1=num1^num2 ;
        num2=num1^num2 ;
        num1=num1^num2 ;    

        System.out.println("After swapping: "+num1+" "+ num2);

    }

}

Approach 5: swap two numbers using a single statement

import java.util.Scanner;

public class Swap {

    public static void main(String[] args) {
        // swap two numbers
        Scanner s = new Scanner(System.in) ;

        System.out.println("Enter first number");
        int num1 = s.nextInt() ;

        System.out.println("Enter second number");
        int num2 = s.nextInt() ;

        System.out.println("Before swapping: "+num1+" "+num2);


        // logic-5 - use single statement
        num2=num1+num2-(num1=num2) ;

        System.out.println("After swapping: "+num1+" "+ num2);

    }

}