succcesfully work on dos but problems in c# ?

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace can
{
    class Program
    {
        static void Main(string[] args)
        {
	    int k;
	    Console.WriteLine("Enter a number whose factorial needs to be calculated: ");
	    k = Convert.ToInt32(Console.ReadLine());

    	int[] numArr = new int[10000];
	    int total,rem=0,count,i;
	    for(i=0;i<9999;i++)
		    numArr[i]=0; 
				
	    numArr[9999]=1; 
	    for(count = 2 ; count <= k ; count++)   
	    {
		    while(i>0)
		    {
			    total = numArr[i] * count + rem;  
			    rem=0;
			    if(total>9)
			    {
				    numArr[i]=total%10;
				    rem=total/10;
			    }
			    else
			    {
				    numArr[i]=total;
			    }
			    i--;             
		    }
		    rem=0;
		    total=0;
		    i=9999;
	    }
	    Console.WriteLine("The factorial of " + k + " is ");
	    for(i=0;i<10000;i++)            
	    {
		    if(numArr[i]!=0 || count==1)  
		    {
		    	Console.Write(numArr[i]);
			    count=1;
		    }
	    }
	    Console.ReadLine();
        }
    }
}