In this example, you will learn to find the factorial of a non-negative integer entered by the user using recursion.

To understand this
example, you should have the knowledge of the following C programming topics:

·
C
Functions

·
C
User-defined functions

· C Recursion

The
factorial of a positive number `n` is
given by:

factorial of n (n!) = 1 * 2 * 3 * 4 *... * n

The
factorial of a negative number doesn't exist. And the factorial of `0`

is `1`

.

You will
learn to find the factorial of a number using recursion in this example. Visit
this page to learn how you can find the factorial of a number using a loop.

## Factorial
of a Number Using Recursion

```
#include <stdio.h>
long int multiplyNumbers(int n);
int main() {
int n;
printf("Enter a positive integer: ");
scanf("%d",&n);
printf("Factorial of %d = %ld", n, multiplyNumbers(n));
return 0;
}
long int multiplyNumbers(int n) {
if (n > =1)
return n*multiplyNumbers(n-1);
else
return 1;
}
```

Output

Enter a positive integer: 6

Factorial of 6 = 720

Suppose the user entered 6.

Initially, multiplyNumbers() is called from main() with
6 passed as an argument.

Then, 5 is passed to multiplyNumbers() from the same function (recursive call). In each
recursive call, the value of argument n is decreased by 1.

When the value of n is less than 1, there is no recursive call and the factorial is returned ultimately to the main() function.

**Labels :**#c ,#code ,#examples ,