Question

Using Java IDE

Write a recursive method which takes an integer number and returns the sum of the numbers from 1 to that number. The method must solve the problem recursively.Then write an application which calls the method with a few different numbers and displays the return value of the method.

Answer 1

//SumN.java
import java.util.Scanner;

public class SumN {
    public static int sumofn(int num) {
        if(num == 0){
            return 0;
        }
        else{
            return num + sumofn(num-1);
        }
    }

    public static void main(String args[]) {
        Scanner scan = new Scanner(System.in);
        System.out.print("Enter a positive integer: ");
        int num = scan.nextInt();
        System.out.println("Sum1 till "+num +" is "+sumofn(num));
    }
}