In this java program, we will learn about how to calculate the sum of natural numbers using recursion.
The natural numbers are the numbers that include all integers from 1 to infinity. To find the sum of all natural number till N, we have to add all numbers between 1 to N.
Let sumNumbers(N) be a method to calculate sum of natural numbers from 1 to N. Then
sumNumbers(N) = 1 + 2 + 3 + ... + N sumNumbers(N) = [1 + 2 + 3 + ... +(N-1)]+ N sumNumbers(N) = sumNumbers(N-1)+ N
From above recursion equation, to calculate natural number sum till N, we have to first calculate sum of natural numbers till (N-1) and then add N.
For Example:
sumNumbers(10) = sumNumbers(9) + 10
To understand this java program, you should have understanding of the following Java programming concepts:
Java program to find the sum of natural numbers using recursion
public class NumbersSumRecursion {
static int sumNumbers(int N) {
if (N == 1) {
return 1;
} else {
return sumNumbers(N - 1) + N;
}
}
public static void main(String[] args) {
int sum = sumNumbers(15);
System.out.println("Sum of Numbers till 15 : "+sum);
}
}
Output
Sum of Numbers till 15 : 120