OOP: Inherintance

OOP: Inherintance

1. Concept

   • Inheritance is specific to object-oriented programming, where a new class is created from an existing class. Inheritance (often referred to as subclasses) comes from the fact that the subclass (the newly created class) contains the attributes and methods of the parent class. The main advantage of inheritance is the ability to define new attributes and new methods for the subclass which are then applied to the inherited attributes and methods.

2. Class Hierarchy

   • The parent-child relationship between classes can be represented in a hierarchical view often called class tree view. The class tree view starts with a general class called superclass (sometimes referred to as base class, parent class, ancestor class, mother class or father class), there are many genealogical metaphors). Derived classes (child class or subclass) become more specialized further down the tree. Therefore we usually refer to the relationship that links one child class to a parent class by the phrase "is a(n) " x of y).

3. Types

   • Single Inheritance
     • Where subclasses inherit the features of one superclass. A class acquires the properties of another class.
   • Hybrid inheritance
     • A mix of two or more of the above types of inheritance.
   • Multilevel Inheritance
     • Where a subclass is inherited from another subclass. It is not uncommon that a class is derived from another derived class as shown in the figure "Multilevel inheritance". Multilevel inheritance The class A serves as a base class for the derived class B, which in turn serves as a base class for the derived class C. The class B is known as intermediate base class because it provides a link for the inheritance between A and C. The chain ABC is known as inheritance path.
   • Hierarchical inheritance
     • Where one class serves as a superclass (base class) for more than one sub class.
   • Multiple Inherintance
     • Where one class can have more than one superclass and inherit features from all parent classes.

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