# C : Find the Sum of Natural Numbers using Recursion

Tutorial by:Manisha Dubey      Date: 2016-06-17 03:50:38

Example to find the sum of natural numbers by using recursion.

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 that number.

## Example: Sum of Natural Numbers Using Recursion

``````#include <stdio.h>

int main()
{
int n;
printf("Enter a positive integer: ");
scanf("%d", &n);
return 0;
}
{
if(n!=0)
else
return n;
}``````

Output

```Enter a positive integer: 20
Sum = 210```

Suppose the user entered 20.

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

In the next function call from `addNumbers()` to `addNumbers()`, 19 is passed. Then, 18 is passed to the function. This process continues until n is equal to 0.

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

## C

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