using System;

public class c1

{

    public int testValue=0;

}

​

public class Program

{

    public static void changeValue(c1 c)

    {

        c = new c1();

        c.testValue = 9;

        return;

    }

    public static void Main()

    {

        c1 c = new c1();

        c.testValue = 5;

        changeValue(c);

        Console.WriteLine(c.testValue);

    }

}