static void Main(string[] args) { UserControl usercontrol = new UserControl(); bool isExit = false; string input; Instruction(); while (!isExit) { input = Console.ReadLine(); Enum.TryParse(input, true, out usercontrol); switch (usercontrol) { case UserControl.Exercise1: Console.WriteLine("Solve of {0}", UserControl.Exercise1); Exercise1 exercise1 = new Exercise1(); exercise1.Show(); break; case UserControl.Exercise2: Console.WriteLine("Solve of {0}", UserControl.Exercise2); Exercise2 exercise2 = new Exercise2(); exercise2.Show(); Vector vector1 = new Vector(10, 10); Vector vector2 = new Vector(15, 15); Console.WriteLine("Scalar multiply {0} of vectors {1} and {2}", vector1 * vector2, vector1, vector2); break; case UserControl.Exercise3: Console.WriteLine("Solve of {0}", UserControl.Exercise3); Exercise3 exercise3 = new Exercise3(); exercise3.Show(); break; case UserControl.Exercise4: Console.WriteLine("Solve of {0}", UserControl.Exercise4); Exercise4 exercise4 = new Exercise4(); exercise4.Show(); break; case UserControl.Exercise5: Console.WriteLine("Solve of {0}", UserControl.Exercise5); Exercise5 exercise5 = new Exercise5(); exercise5.Show(); break; case UserControl.Exit: isExit = true; break; default: Instruction(); break; } } }