c#实验7.2：阶乘的异常处理

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

namespace ConsoleApplication1
{
class overflowRange : ApplicationException
{
public overflowRange(string msg)
: base(msg)
{ }
}
class Program
{
static void Main(string[] args)
{
try
{
Console.Write("请输入一个数：");
double x = double.Parse(Console.ReadLine());
int y = (int)x;
if (x > (double)y || (double)y < x)
{
throw new overflowRange("你输入的数应该为整数！");
}
if (x == y)
{
int sum = 1;
for (int i = 1; i <= x; i++)
{
sum = sum * i;
}
Console.WriteLine("该数的阶乘为：" + sum);
}
}
catch (overflowRange e)
{
Console.WriteLine(e.Message);
}
finally
{
Console.WriteLine("按任意键退出...");
Console.ReadKey();
}
}
}
}