Inheritance is one of the most characters of classes.
class phone { public double weight; public string make; public phone(string m) {make=m;} public string dial() {return "keyboard";} public string imake { get { return make; } set { make = value; } } } class smartphone : phone { double screenwidth; double screenheight; public string dial() {return "touch screen";} public smartphone(string m,double w, double h) : base(m) {make=m;screenwidth=w;screenheight=h;} }
smartphone sp = new smartphone("Apple",6.2,10); sp.imake = "Samsung";
sp.dial(); //touch screen
sealed class tv {...} class smartphone : tv {...} //error
class camera {...} class smartphone : phone, camera { ... }