C# program to find the factorial of a number

In this article we will discuss with you the program for calculating the factorial of a number using console application in c#.net:

Step1: Take a new console application using c# as a language in the Visual studio.

Step2: Read an input from the User in this Variable “int_Number” for storing that number whose factorial you want to find out.

Step3: Now if that input number is 1 or 0 then its factorial will be 1 otherwise we have to loop from the input number till 1 and multiply the input no with its immediate lower number till 1.

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace PrimeNo

{

    class Program

    {

        static void Main()

        {

           

            int int_number;

            long ln_num;

            ln_num = 1;

            Console.WriteLine("please enter the number whose factorial you want to find");

            int_number = int.Parse(Console.ReadLine());

            if ((int_number == 1) || (int_number == 0))

            {

                Console.WriteLine("factorial of the number "+int_number+ " is 1.");

            }

            else

            {

                for (int i = int_number; i >= 1; i--)

                {

                    ln_num = ln_num * i;

                }

                Console.WriteLine("factorial of the number " + int_number + " is " +ln_num );

            }

            Console.ReadLine();

       }

    }

}

Output:-