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Virtual Inheritance
Virtual inheritance is a C++ technique that ensures only one copy of a base classs member variables are inherited by grandchild derived classes. Without virtual inheritance, if two classes B and C inherit from a class A, and a class D inherits from both B and C, then D will contain two copies of As member variables: one via B, and one via C. These will be accessible independently, using scope resolution. Instead, if classes B and C inherit virtually from class A, then objects of class D will contain only one set of the member variables from class A. This feature is most useful for multiple inheritance, as it makes the virtual base a common subobject In category theory, a branch of mathematics, a subobject is, roughly speaking, an object that sits inside another object in the same category. The notion is a generalization of concepts such as subsets from set theory, subgroups from group theory ... for the deriving class and all classes that are derived from it. This can be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diamond Inheritance
Multiple inheritance is a feature of some object-oriented computer programming languages in which an object or class can inherit features from more than one parent object or parent class. It is distinct from single inheritance, where an object or class may only inherit from one particular object or class. Multiple inheritance has been a controversial issue for many years, with opponents pointing to its increased complexity and ambiguity in situations such as the "diamond problem", where it may be ambiguous as to which parent class a particular feature is inherited from if more than one parent class implements said feature. This can be addressed in various ways, including using virtual inheritance. Alternate methods of object composition not based on inheritance such as mixins and traits have also been proposed to address the ambiguity. Details In object-oriented programming (OOP), ''inheritance'' describes a relationship between two classes in which one class (the ''child'' class ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inheritance (object-oriented Programming)
In object-oriented programming, inheritance is the mechanism of basing an Object (computer science), object or Class (computer programming), class upon another object (Prototype-based programming, prototype-based inheritance) or class (Class-based programming, class-based inheritance), retaining similar implementation. Also defined as deriving new classes (#Subclasses and superclasses, sub classes) from existing ones such as super class or Fragile base class, base class and then forming them into a hierarchy of classes. In most class-based object-oriented languages like C++, an object created through inheritance, a "child object", acquires all the properties and behaviors of the "parent object", with the exception of: Constructor (object-oriented programming), constructors, destructors, operator overloading, overloaded operators and friend functions of the base class. Inheritance allows programmers to create classes that are built upon existing classes, to specify a new implementat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scope Resolution Operator
In computer programming, scope is an enclosing context where values and expressions are associated. The scope resolution operator helps to identify and specify the context to which an identifier refers, particularly by specifying a namespace or class. The specific uses vary across different programming languages with the notions of scoping. In many languages, the scope resolution operator is written ::. In some languages, notably those influenced by Modula-3 (including Python and Go), modules are objects, and scope resolution within modules is a special case of usual object member access, so the usual method operator . is used for scope resolution. Other languages, notably C++ and Ruby, feature both scope resolution and method access, which interact in various ways; see examples below. C++ class A ; namespace B // namespace B int A::i = 4; // scope operator refers to the integer i declared in the class A int x = B::c; // scope operator refers to the integer c declared ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multiple Inheritance
Multiple inheritance is a feature of some object-oriented computer programming languages in which an object or class can inherit features from more than one parent object or parent class. It is distinct from single inheritance, where an object or class may only inherit from one particular object or class. Multiple inheritance has been a controversial issue for many years, with opponents pointing to its increased complexity and ambiguity in situations such as the "diamond problem", where it may be ambiguous as to which parent class a particular feature is inherited from if more than one parent class implements said feature. This can be addressed in various ways, including using virtual inheritance. Alternate methods of object composition not based on inheritance such as mixins and traits have also been proposed to address the ambiguity. Details In object-oriented programming (OOP), ''inheritance'' describes a relationship between two classes in which one class (the ''child'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Subobject
In category theory, a branch of mathematics, a subobject is, roughly speaking, an object that sits inside another object in the same category. The notion is a generalization of concepts such as subsets from set theory, subgroups from group theory,Mac Lane, p. 126 and subspaces from topology. Since the detailed structure of objects is immaterial in category theory, the definition of subobject relies on a morphism that describes how one object sits inside another, rather than relying on the use of elements. The dual concept to a subobject is a . This generalizes concepts such as quotient sets, quotient groups, quotient spaces, quotient graphs, etc. Definitions An appropriate categorical definition of "subobject" may vary with context, depending on the goal. One common definition is as follows. In detail, let ''A'' be an object of some category. Given two monomorphisms :u: S \to A \ \text \ v: T\to A with codomain ''A'', we define an equivalence relation by u \equiv v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diamond Problem
Multiple inheritance is a feature of some object-oriented computer programming languages in which an object or class can inherit features from more than one parent object or parent class. It is distinct from single inheritance, where an object or class may only inherit from one particular object or class. Multiple inheritance has been a controversial issue for many years, with opponents pointing to its increased complexity and ambiguity in situations such as the "diamond problem", where it may be ambiguous as to which parent class a particular feature is inherited from if more than one parent class implements said feature. This can be addressed in various ways, including using virtual inheritance. Alternate methods of object composition not based on inheritance such as mixins and traits have also been proposed to address the ambiguity. Details In object-oriented programming (OOP), ''inheritance'' describes a relationship between two classes in which one class (the ''child'' c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Keyword (computer Programming)
Keyword may refer to: Computing * Index term, a term used as a keyword to documents in an information system such as a catalog or a search engine * Keyword (Internet search), a word or phrase typically used by bloggers or online content creator to rank a web page on a particular topic * A reserved word in a programming language Other uses * Keyword (linguistics), a word that occurs in a text more often than by chance alone * '' Keywords: A Vocabulary of Culture and Society'', 1973 non-fiction book by Raymond Williams * "Keyword" (song), a 2008 song by Tohoshinki See also *Buzzword A buzzword is a word or phrase, new or already existing, that becomes popular for a period of time. Buzzwords often derive from technical terms yet often have much of the original technical meaning removed through fashionable use, being simply ... * Trigger word *Related to index terms: ** Key Word in Context ** Keyword advertising, a form of online advertising ** Keyword clustering, a search ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
UML Virtual Inheritance
The Unified Modeling Language (UML) is a general-purpose visual modeling language that is intended to provide a standard way to visualize the design of a system. UML provides a standard notation for many types of diagrams which can be roughly divided into three main groups: behavior diagrams, interaction diagrams, and structure diagrams. The creation of UML was originally motivated by the desire to standardize the disparate notational systems and approaches to software design. It was developed at Rational Software in 1994–1995, with further development led by them through 1996. In 1997, UML was adopted as a standard by the Object Management Group (OMG) and has been managed by this organization ever since. In 2005, UML was also published by the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IEC) as the ISO/IEC 19501 standard. Since then the standard has been periodically revised to cover the latest revision of UML. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Is-a
In knowledge representation, ontology components and ontology engineering, including for object-oriented programming and design, is-a (also written as is_a or is a) is a subsumptive relationship between abstractions (e.g., types, classes), wherein one class ''A'' is a subclass of another class ''B'' (and so ''B'' is a superclass of ''A''). In other words, type A is a subtype of type B when A's specification implies B's specification. That is, any object (or class) that satisfies A's specification also satisfies B's specification, because B's specification is weaker. For example, a cat 'is a animal, but not vice versa. All cats are animals, but not all animals are cats. Behaviour that is relevant to all animals is defined on an animal class, whereas behaviour that is relevant only for cats is defined in a cat class. By defining the cat class as 'extending' the animal class, all cats 'inherit' the behaviour defined for animals, without the need to explicitly code that behavi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diamond Problem
Multiple inheritance is a feature of some object-oriented computer programming languages in which an object or class can inherit features from more than one parent object or parent class. It is distinct from single inheritance, where an object or class may only inherit from one particular object or class. Multiple inheritance has been a controversial issue for many years, with opponents pointing to its increased complexity and ambiguity in situations such as the "diamond problem", where it may be ambiguous as to which parent class a particular feature is inherited from if more than one parent class implements said feature. This can be addressed in various ways, including using virtual inheritance. Alternate methods of object composition not based on inheritance such as mixins and traits have also been proposed to address the ambiguity. Details In object-oriented programming (OOP), ''inheritance'' describes a relationship between two classes in which one class (the ''child'' c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vtable
In computer programming, a virtual method table (VMT), virtual function table, virtual call table, dispatch table, vtable, or vftable is a mechanism used in a programming language to support dynamic dispatch (or run-time method binding). Whenever a class defines a virtual function (or method), most compilers add a hidden member variable to the class that points to an array of pointers to (virtual) functions called the virtual method table. These pointers are used at runtime to invoke the appropriate function implementations, because at compile time it may not yet be known if the base function is to be called or a derived one implemented by a class that inherits from the base class. There are many different ways to implement such dynamic dispatch, but use of virtual method tables is especially common among C++ and related languages (such as D and C#). Languages that separate the programmatic interface of objects from the implementation, like Visual Basic and Delphi, also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
