C # Abstract class

1. Abstract modifier of the abstract class. Example: public abstract class name
2. Abstract classes cannot be instantiated.
3. An abstract class can be inherited. However, if an abstract class contains an abstract method (with an abstract modifier), the derived class must implement the abstract method in the inherited abstract class.
   Public abstract class thc123_com
   {
   Public abstract void GOTO ();
   }

   Public class thc123_net: thc123_com
   {
   Public override void GOTO ()
   {
   // Implement the preceding abstract Method
   }
   }

4. If the abstract class only contains abstract methods, the form is the same as that of the interface.