static void Main(string[] args) { var tea = new Tea(); var coffee = new Coffee(); tea.WantsCondiments = true; tea.AddSugar = 5; tea.Prepare(); Console.WriteLine(); coffee.WantsCondiments = true; coffee.Prepare(); var people = new List <Person> { new Person("Ram", 25), new Person("Abishek", 12), new Person("Ram", 18), new Person("Abishek", 18) }; foreach (var person in people) { Console.Write(person); } people.Sort(); Console.WriteLine(); foreach (var person in people) { Console.Write(person); } }