# Java Program to Find the Sum of Natural Numbers using Recursion

#### In this program, you’ll learn to find the sum of natural number using recursion in Java. This is done with the help of a recursive function.

The positive numbers 1, 2, 3… are known as natural numbers. The program below takes a positive integer from the user and calculates the sum up to the given number.

## Example: Sum of Natural Numbers Using Recursion

``````

public static void main(String[] args){
int number = 20;
int sum = addNumbers(number);
System.out.println("Sum = " + sum);
}

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

Output

`Sum = 210`

The number whose sum is to be found is stored in a variable number.

Initially, the `addNumbers()` is called from the `main()` function with 20 passed as an argument.

The number (20) is added to the result of `addNumbers(19)`.

In the next function call from `addNumbers()` to `addNumbers()`, 19 is passed which is added to the result of `addNumbers(18)`. This process continues until num is equal to 0.

When num is equal to 0, there is no recursive call and this returns the sum of integers to the `main()` function.

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