C Program to find the Factorial of a Given Number

Problem

Write a program in C programming language to find the factorial of a given number and display it on the screen.

How to find the factorial of a Number in C?

The factorial of a number is generally specified as follows

N! = 1*2*3*4… N

This applies only for the positive number. The factorial of 0 is considered to be 1.

Here’s a program in C demonstrating the factorial of a number.

#include <stdio.h>
int main()
{
    printf("Abundantcode.com coding samples\n");
    int N,index ;
    long factorial = 1;

    printf("Enter a positive integer: ");
    scanf("%d",&N);

    if (N < 0)
        printf("Invalid number");

    else
    {
        for(index=1; index<=N; ++index)
        {
            factorial *= index;              
        }
        printf("Factorial of %d = %llu", N, factorial);
    }

    return 0;
}

Output

Abundantcode.com coding samples

Enter a positive integer: 4

Factorial of 4 = 24

%d