Abstract Base Class C Objects

Abstract classes cannot be used to instantiate objects and serves only as an interface.

Abstract base class c objects. An abstract class contains at least one pure virtual function. As we look at the c language we could say that an abstract base class has one or more pure virtual member functions. However you can use pointers and references to abstract class types. You cannot create an object of an abstract class type.

If we want to make a class abstract in java we use the abstract keyword. The term shape is an abstract concept it could be a circle a square etc etc. A pure virtual function is declared by assigning 0 in declaration. Abstract classes apart from pure virtual functions can have member variables non virtual functions regular virtual functions static functions etc.

Classes inheriting an abstract class must provide definition to the pure virtual function otherwise they will also become abstract class. Attempting to instantiate an object of an abstract class causes a compilation error. The purpose of an abstract class often referred to as an abc is to provide an appropriate base class from which other classes can inherit. See the following example.

Abstract class in c. The syntax is to replace their definition by 0 an equal sign and a zero. Abstract classes act as expressions of general concepts from which more specific classes can be derived. An abstract class is a class that is designed to be specifically used as a base class.

Abstract base classes are something very similar to the polygon class in the previous example. Similarly we can make pure virtual functions to make the class the class abstract. Abstract classes are used to provide an interface for its sub classes. In c we dont need to add an abstract keyword as the base class which has at least one pure virtual function is understood to be an abstract class.

A pure virtual function or abstract function in c is a virtual function for which we dont have implementation we only declare it. 2 minutes to read 2. You could say in c that class cshape is an abstract base class abc and class circle etc could be a derived class. Abstract classes c 11042016.

You declare a pure virtual function by using a pure specifier 0 in the declaration of a virtual member function in the class declaration. They are classes that can only be used as base classes and thus are allowed to have virtual member functions without definition known as pure virtual functions. The following is an example of an abstract class.