static void Main(string[] args) { Value val1 = new Value(2); Value val2 = new Value(7); Value val3 = new Value(2); Value val4 = new Value(8); Write.Do(val1, val2); Console.WriteLine("after do : {0}; {1} ", val1.i, val2.i); Write.Do1(ref val3, val4); Console.WriteLine("after do1 : {0}; {1} ", val3.i, val4.i); Console.ReadLine(); }