Unlock the Power of Recursion: Calculating the Sum of Natural Numbers

The Problem Statement

Given a positive integer, find the sum of all natural numbers up to that number. For instance, if the input is 20, the output should be the sum of all natural numbers from 1 to 20.

How Recursion Comes into Play

To tackle this problem using recursion, we’ll create a function that calls itself repeatedly until a base case is reached. In this case, the base case is when the input number reaches 0.

The process works as follows:

• The user inputs a positive integer, which is stored in the number variable.
• The addNumbers() function is called from the main() function, passing the input number as an argument.
• The addNumbers() function adds the current number to the result of calling itself with the previous number (e.g., addNumbers(19) if the current number is 20).
• This process continues until the input number reaches 0, at which point the recursive calls cease, and the sum of integers is returned to the main() function.

Java Code Solution

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

  public static void main(String[] args) {
    int number = 20; // input number
    int sum = addNumbers(number);
    System.out.println("The sum of natural numbers up to " + number + " is " + sum);
  }
}

By harnessing the power of recursion, we can elegantly solve this problem and unlock a deeper understanding of programming concepts.