Java Program to Subtract Two Numbers Using Recursion

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In this article we are going to see how we can subtract two numbers using recursion by Java programming language.

Java Program to Subtract Two Numbers Using Recursion

Method-1: Java Program to Subtract Two Numbers Using Recursion By Using Static Input Value

Approach:

  • Store two numbers in two variables.
  • Call the user defined method sub( ) to find the difference and store it. The method sub() decrements both the numbers by 1 using recursion until the smaller one reaches 0. Then it returns the other number.
  • Print the result.

Program:

import java.util.*;
// Main class
public class Main
{
    // Recursive method to subtract two numbers
    public static int sub(int num1, int num2)
    {
        // Returns the difference when num2 reaches zero
        if(num2==0)
            return num1;
        else
            // calls the function by decrementing both numbers by 1
            return sub((num1-1),(num2-1));
    }
    
    public static void main(String[] args)
    {
        int num1 = 29, num2 = 15;
        // Call the method and store the result
        int dif = sub(num1,num2);
        // Print the result
        System.out.println("The difference between "+num1+" and "+num2+" is "+dif);
    }
}

Output:

The difference between 29 and 15 is 14

Method-2: Java Program to Subtract Two Numbers Using Recursion By Using User Input Value

Approach:

  • Ask the user to enter two numbers in order.
  • Store two numbers in two variables.
  • Call the user defined method sub( ) to find the difference and store it. The method sub() decrements both the numbers by 1 using recursion until the smaller one reaches 0. Then it returns the other number.
  • Print the result.

Program:

import java.util.*;
// Main class
public class Main
{
    // Recursive method to subtract two numbers
    public static int sub(int num1, int num2)
    {
        // Returns the difference when num2 reaches zero
        if(num2==0)
            return num1;
        else
        // calls the function by decrementing both numbers by 1
            return sub((num1-1),(num2-1));
    }
    
    public static void main(String[] args)
    {
        // Taking user input
        Scanner sc = new Scanner(System.in);
        // Ask the user to enter two numbers
        System.out.print("Enter two numbers to subtract ");
        int num1 = sc.nextInt(), num2 = sc.nextInt();
        // Call the method and store the result
        int dif = sub(num1,num2);
        // Print the result
        System.out.println("The difference between "+num1+" and "+num2+" is "+dif);
    }
}

Output:

Enter two numbers to subtract 10 5
The difference between 10 and 5 is 5

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