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;
}
}
return value;
}
}
}