using System; //using System.Security; public class itest2 { public static void Main(string[] args) { itest1 obj = new itest1(); Console.WriteLine(obj.f(3)); itest1 obj2 = new itest1(); obj.add(obj2); Console.WriteLine(obj.getx()); Console.WriteLine(obj2.getx()); } // main } // compile with csc /r:itest1.dll itest2.cs