Factorial Number Program in C#

The factorial, symbolized by an exclamation mark (!), is a quantity defined for all integer s greater than or equal to 0.

For an integer n greater than or equal to 1, the factorial is the product of all integers less than or equal to n but greater than or equal to 1. The factorial value of 0 is defined as equal to 1. The factorial values for negative integers are not defined. Let's see a C# language program that show factorial value of user input number.

using System;

namespace FactorialExample

{

class Program

{

static void Main(string[] args)

{

Console.WriteLine("Enter a number");

int number = Convert.ToInt32(Console.ReadLine());

long fact = GetFactorial(number);

Console.WriteLine("{0} factorial is {1}", number, fact);

Console.ReadKey();

}

private static long GetFactorial(int number)

{

int value = 1;

if (number == 0)

{

return 1;

}

else

{

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

{

value *= i;

}

}