Search results
Results from the WOW.Com Content Network
The empty set is the unique initial object in Set, the category of sets.Every one-element set is a terminal object in this category; there are no zero objects.. Similarly, the empty space is the unique initial object in Top, the category of topological spaces and every one-point space is a terminal object in thi
In object-oriented computer programming, a null object is an object with no referenced value or with defined neutral (null) behavior.The null object design pattern, which describes the uses of such objects and their behavior (or lack thereof), was first published as "Void Value" [1] and later in the Pattern Languages of Program Design book series as "Null Object".
In object-oriented programming, objects have methods that can change or use the object's data. Many programming languages use a special word, like this or self , to refer to the current object. In languages that support open recursion , a method in an object can call other methods in the same object, including itself, using this special word.
A section of code that performs such initialization is generally known as "initialization code" and may include other, one-time-only, functions such as opening files; in object-oriented programming, initialization code may be part of a constructor (class method) or an initializer (instance method).
In C++, objects are created on the stack when the constructor is invoked without the new operator, and created on the heap when the constructor is invoked with the new operator. Stack objects are deleted implicitly when they go out of scope, while heap objects must be deleted implicitly by a destructor or explicitly by using the delete operator.
In mathematics, the category Ord has preordered sets as objects and order-preserving functions as morphisms.This is a category because the composition of two order-preserving functions is order preserving and the identity map is order preserving.
Ownership of dynamically allocated objects (memory allocated with new in C++) can also be controlled with RAII, such that the object is released when the RAII (stack-based) object is destroyed. For this purpose, the C++11 standard library defines the smart pointer classes std::unique_ptr for single-owned objects and std::shared_ptr for objects ...
The initial object of Cat is the empty category 0, which is the category of no objects and no morphisms. [1] The terminal object is the terminal category or trivial category 1 with a single object and morphism. [2] The category Cat is itself a large category, and therefore not an object of itself.