Program no: 7(C) C program to find Factorial of a Number using Reccursion

C program to find the factorial using recurrsion

Write a recursive function in C to find factorial of a number. How to find factorial of a number using recursion in C program. Logic to find factorial of a number using recursion in C programming

Example

Input

Input any number: 5

Output

Factorial of 5 = 120

Required knowledge

Basic C programming, If else, Functions, Recursion

1. First let us give a meaningful name to our function, say fact().
2. The factorial function accepts an integer input whose factorial is to be calculated. Hence the function declaration should look like fact(int num);.
3. The function returns factorial as an integer value. Since, factorial can grow rapidly hence the suitable return type for this function is unsigned long long.
   The above mathematical function defines a recursive approach to find factorial of a number.
   Factorial of 0 is 1 which is our base condition i.e. if(num == 0) return 1;. If number is positive then return product of n and factorial of n-1. To find factorial of n-1 we make a recursive function call to our factorial function i.e. num * fact(num - 1)

 Source code:

Here we have the codes!! 

#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;
}