Write a C# program to calculate a factorial using recursion

Factorial of a number is what we are finding using a recursive function checkFact () in the below example −

If the value is 1, it returns 1 since Factorial is 1 −

if (n == 1)
return 1;

If not, then the recursive function will be called for the following iterations if you want the value of 5!

Interation1:
5 * checkFact (5 - 1);

Interation2:
4 * checkFact (4 - 1);

Interation3:
3 * checkFact (3 - 1);

Interation4:
4 * checkFact (2 - 1);

To calculate a factorial using recursion, you can try to run the following code which shows what is done above −

Example

 Live Demo

using System;

namespace Demo {

   class Factorial {

      public int checkFact(int n) {
         if (n == 1)
         return 1;
         else
         return n * checkFact(n - 1);
      }

      static void Main(string[] args) {

         int value = 9;
         int ret;

         Factorial fact = new Factorial();
         ret = fact.checkFact(value);
         Console.WriteLine("Value is : {0}", ret );
         Console.ReadLine();
      }
   }
}

Output

Value is : 362880