C Programming Code Examples C > Recursion Code Examples C Program to Find Factorial of a Number Using Recursion C Program to Find Factorial of a Number Using 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. #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; }