获取stackoverflowexception，不知道为什么。有人可以帮忙吗？

我对此并不陌生，我会逐步按照说明进行操作，但是由于某种原因，请继续获取stackoverflowexception。我究竟做错了什么？

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

namespace assignment3
{
    class changeValue
    {
        //Create a class called changeValue that declares 2 integer class variables:  value1 and 
        //  value2.  These should be declared as public and you should not use automatic properties 
        // to declare them. 
        public int value1
        {
            get
            {
                return value1;
            }//end get
            set
            {
                value1 = value;
            }//end set
        }
        public int value2
        {
            get
            {
                return value2;
            }//end get
            set
            {
                value2 = value;
            }//end set
        }

    public changeValue(int val1, int val2)
    {
        //here is the constructor where you code the if statements
        int value1 = val1;
        int value2 = val2;

        if (value1 > 5)
        { 
            value1 = val1; 
        }
        if (val1 <= 5)
        {
            value1 = (val1+val2);
        }
        if (val2 < 10)
        {
            value2 = (val2 * val2 + 5);
        }
        if (val2 >= 10)
        {
            value2 = val2;
        }
    }

    public void printit()
    {
        //here is the printit method used to print the results
       Console.WriteLine("The calculated value is:" + (value1 * value2));

    }
}
class assignment3
{
    public static void Main(string[] args)
    {
        //declare the local val1 and val2 integer variables
        int val1;
        int val2;    

        //prompt the user for input of two integers
        //don’t forget to convert from the string input to integer
        Console.Write("Enter an integer value: "); //obtain user input
        val1 = Convert.ToInt32(Console.ReadLine());

        Console.Write("Enter a second integer value: "); //obtain user input
        val2 = Convert.ToInt32(Console.ReadLine());

        //instantiate a changeValue object here
        changeValue myValue = new changeValue(val1,val2);

        myValue.printit();//call the object method printit here
    }
}
}