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When overriding one method with another, the signatures of the two methods must be identical (and with same visibility). In C#, class methods, indexers, properties and events can all be overridden. Non-virtual or static methods cannot be overridden. The overridden base method must be virtual, abstract, or override.
Method overriding and overloading are two of the most significant ways that a method differs from a conventional procedure or function call. Overriding refers to a subclass redefining the implementation of a method of its superclass.
In Qt, QMainWindow::createPopupMenu Archived 2015-07-19 at the Wayback Machine is a factory method declared in a framework that can be overridden in application code. In Java, several factories are used in the javax.xml.parsers package, such as javax.xml.parsers.DocumentBuilderFactory or javax.xml.parsers.SAXParserFactory.
Rather, the derived class only needs to implement (override) the methods having different behavior than the base class methods. This can require significantly less programming effort if the base class contains many methods providing default behavior and only a few of them need to be overridden within the derived class.
If there are base class methods overridden by the derived class, the method actually called by such a reference or pointer can be bound (linked) either "early" (by the compiler), according to the declared type of the pointer or reference, or "late" (i.e., by the runtime system of the language), according to the actual type of the object is ...
Also, derived classes can override inherited methods if the language allows. Not all languages support multiple inheritance. For example, Java allows a class to implement multiple interfaces, but only inherit from one class. [22] If multiple inheritance is allowed, the hierarchy is a directed acyclic graph (or DAG for short), otherwise it is a ...
To override the default behavior, one simply qualifies a method call with the desired class definition. Perl uses the list of classes to inherit from as an ordered list. The compiler uses the first method it finds by depth-first searching of the superclass list or using the C3 linearization of the class hierarchy.
The same function name is used for more than one function definition in a particular module, class or namespace; The functions must have different type signatures, i.e. differ in the number or the types of their formal parameters (as in C++) or additionally in their return type (as in Ada).