c# faktöriyel hesaplama yardım

 
  private int carp(int sayi1, int sayi2) { 
   
     int sonuc = sayi2; 
     for(int i = 1; i < sayi1; i++) 
        sonuc = sonuc + sayi2; 
   
     return sayi2; 
   
  } 
  

private int factorial(int baseNumber, int decreasingNumber){ // Fonksiyon Kullanım Ornegı: factorial(5,4) , 5! bulmak icin 
  		 
  		if(baseNumber == 0) // Exception case for input: '0' 
  			return 1;	 
  		if(decreasingNumber == 0 ) 
  			return baseNumber; 
  		else{ 
  			int temp = 0; 
  			for(int i = 0; i < baseNumber; i++){ 
  				temp += decreasingNumber; 
  			} 
  			return factorial(temp,--decreasingNumber); 
  		} 
  		 
  	}

 
  using System; 
  using System.Collections.Generic; 
  using System.Linq; 
  using System.Text; 
   
   
      class Program // Buraya kendi class ismini yazman gerekiyor! 
      { 
          static void Main(string[] args) 
          { 
   
              int x = factorial(6, 5); 
              Console.WriteLine(x); 
   
          } 
          private static int factorial(int baseNumber, int decreasingNumber) 
          { // Fonksiyon Kullanım Ornegı: factorial(5,4) , 5! bulmak icin 
   
              if (baseNumber == 0) // Exception case for input: '0' 
                  return 1; 
              if (decreasingNumber == 0) 
                  return baseNumber; 
              else 
              { 
                  int temp = 0; 
                  for (int i = 0; i < baseNumber; i++) 
                  { 
                      temp += decreasingNumber; 
                  } 
                  return factorial(temp, --decreasingNumber); 
              } 
   
          } 
   
  }