using System;
namespace Start
{
    class StartOne
    {
        static void Main(String[] args)
        {
            Console.WriteLine("------------------------------------------");
            Console.WriteLine("                1. 加法运算");
            Console.WriteLine("|                                        |");
            Console.WriteLine("                2. 减法运算");
            Console.WriteLine("|                                        |");
            Console.WriteLine("                3. 乘法运算");
            Console.WriteLine("|                                        |");
            Console.WriteLine("                4. 除法运算");
            Console.WriteLine("|                                        |");
            Console.WriteLine("                5. 退    出");
            Console.WriteLine();
            Console.WriteLine("------------------------------------------");
            Console.WriteLine("请输入想使用的功能：");
            Function function = new Function();
            function.functionNum = Convert.ToInt32(Console.ReadLine());
            Operation operation = new Operation();
            Console.Write("请输入第一个数：");
            operation.AddNum1 = Convert.ToInt32(Console.ReadLine());
            Console.Write("请输入第二个数：");
            operation.AddNum2 = Convert.ToInt32(Console.ReadLine());
            if (function.functionNum == 1)
                operation.Add();
            else if (function.functionNum == 2)
                operation.Subtraction();
            else if (function.functionNum == 3)
                operation.Multiplication();
            else if (function.functionNum == 4)
                operation.Division();
            else 
                Console.WriteLine("感谢您的使用，即将退出！！！");
            operation.Result();
            Console.WriteLine(function.result);
            Console.ReadKey();
            


            
           
            
        }
    }
    
    class Function
    {
        public int functionNum;
        public string result="结果为：";

    }
    class Operation
    {
        public int AddNum1, AddNum2, AddNum3;

        public int Add()
        {
            AddNum3 = AddNum1 + AddNum2;
            return AddNum3;
        }
        public void Subtraction()
        {
            AddNum3 = AddNum1 - AddNum2;
        }
        public void Multiplication()
        {
            AddNum3 = AddNum1 * AddNum2;
        }
        public void Division()
        {
            double DAddNum1 = Convert.ToDouble(AddNum1);
            double DAddNum2 = Convert.ToDouble(AddNum2);
            double DAddNum3 = Convert.ToDouble(AddNum3);
            DAddNum3 = DAddNum1 / DAddNum2;
        }
        public string Result()
        {
            
            Function function = new Function();
            if (function.functionNum == 1)
                function.result = "结果为:" + AddNum3;
            return function.result;
        }
    }
}
为啥在运行的时候会抛出异常{System.StackOverflowException:“Exception_WasThrown”}