Three Different ways to calculate factorial in C#

To calculate a factorial in C#, you can use any of the following three ways −

Calculate factorial with for loop

Example

Live Demo

using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace factorial {    class Test {       static void Main(string[] args) {          int i, res;          int value = 5;          res = value;          for (i = value - 1; i >= 1; i--) {             res = res * i;          }          Console.WriteLine("
Factorial of "+value+" = "+res);          Console.ReadLine();       }    } }

Output

Factorial of 5 = 120

Calculate factorial with a while loop

Example

Live Demo

using System; namespace MyApplication {    class Factorial {       public int display(int n) {          int res = 1;          while (n != 1) {             res = res * n;             n = n - 1;          }          return res;       }       static void Main(string[] args) {          int value = 5;          int ret;          Factorial fact = new Factorial();          ret = fact.display(value);          Console.WriteLine("Value is : {0}", ret );          Console.ReadLine();       }    } }

Output

Value is : 120

Calculate factorial using recursion

Example

Live Demo

using System; namespace MyApplication {    class Factorial {       public int display(int n) {          if (n == 1)             return 1;          else             return n * display(n - 1);       }       static void Main(string[] args) {          int value = 5;          int ret;          Factorial fact = new Factorial();          ret = fact.display(value);          Console.WriteLine("Value is : {0}", ret );          Console.ReadLine();       }    } }

Output

Value is : 120