using System;
 
     class Test
    {
        public string str = "A";
    }
 
    class Program
    {
        static void change1(Test t)
        {
            t.str = "B";
        }
        static void change2(Test t)
        {
            t = new Test();
            t.str = "B";
        }
 
        static void Main(string[] args)
        {
            Test t1 = new Test();
            change1(t1);
            Console.WriteLine(t1.str);
 
            Test t2 = new Test();
            change2(t2);
            Console.WriteLine(t2.str);
        }
    }

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