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Together this implies that a class in Smalltalk is an object and that, therefore a class needs to be an instance of a class (called metaclass). As an example, a car object c is an instance of the class Car. In turn, the class Car is again an object and as such an instance of the metaclass of Car called Car class. Note the blank in the name of ...
The overridden base method must be virtual, abstract, or override. In addition to the modifiers that are used for method overriding, C# allows the hiding of an inherited property or method. This is done using the same signature of a property or method but adding the modifier new in front of it. [6] In the above example, hiding causes the following:
[2] An abstraction and its implementation should be defined and extended independently from each other. A compile-time binding between an abstraction and its implementation should be avoided so that an implementation can be selected at run-time. When using subclassing, different subclasses implement an abstract class in different ways.
In languages supporting multiple inheritance, such as C++, interfaces are implemented as abstract classes. In languages without explicit support, protocols are often still present as conventions. This is known as duck typing. For example, in Python, any class can implement an __iter__ method and be used as a collection. [3]
Interfaces and abstract classes are similar. The following describes some important differences: An abstract class may have member variables as well as non-abstract methods or properties. An interface cannot. A class or abstract class can only inherit from one class or abstract class. A class or abstract class may implement one or more interfaces.
This is where one class serves as a superclass (base class) for more than one sub class. For example, a parent class, A, can have two subclasses B and C. Both B and C's parent class is A, but B and C are two separate subclasses. Hybrid inheritance Hybrid inheritance is when a mix of two or more of the above types of inheritance occurs.
As an example, an abstract base class MathSymbol may provide a pure virtual function doOperation(), and derived classes Plus and Minus implement doOperation() to provide concrete implementations. Implementing doOperation() would not make sense in the MathSymbol class, as MathSymbol is an abstract concept whose behaviour is defined solely for ...
C# (/ ˌ s iː ˈ ʃ ɑːr p / see SHARP) [b] is a general-purpose high-level programming language supporting multiple paradigms.C# encompasses static typing, [16]: 4 strong typing, lexically scoped, imperative, declarative, functional, generic, [16]: 22 object-oriented (class-based), and component-oriented programming disciplines.