Abstract Example

abstract class BaseClass // Abstract class { protected int _x = 100; protected int _y = 150; public abstract void AbstractMethod(); // Abstract method public abstract int X { get; } public abstract int Y { get; } } class Program : BaseClass { ///

/// Abstract Class /// /// Use the abstract modifier in a method or property declaration to indicate that the method /// or property does not contain implementation. /// Use the abstract modifier in a class declaration to indicate that a class is intended only /// to be a base class of other classes. /// The abstract modifier can be used with classes, methods, properties, indexers, and events. /// /// -An abstract class cannot be instantiated. /// -An abstract class class cannot be inherited. /// -An abstract class may contain abstract methods and accessors. /// -A non-abstract class derived from an abstract class must include actual implementations /// of all inherited abstract methods and accessors. /// /// Abstract methods /// /// -An abstract method is implicitly a virtual method. /// -Abstract method declarations are only permitted in abstract classes. /// -It is an error to use the static or virtual modifiers in an abstract method declaration. /// /// Abstract properties /// /// -Abstract properties behave like abstract methods, except for the differences in declaration and invocation syntax. /// -It is an error to use the abstract modifier on a static property. /// -An abstract inherited property can be overridden in a derived class by including a property declaration that uses /// the override modifier. /// /// /// An abstract class must provide implementation for all interface members. /// /*interface I { void M(); } abstract class C: I { public abstract void M(); } */ public override void AbstractMethod() { _x++; _y++; } public override int X // overriding property { get { return _x + 10; } } public override int Y // overriding property { get { return _y + 10; } } static void Main(string[] args) { Program o = new Program(); o.AbstractMethod(); Console.WriteLine("x = {0}, y = {1}", o.X, o.Y); Console.ReadKey(); /*Output x = 111, y = 161*/ } }