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In computer science, an instance is an occurrence of a software element that is based on a type definition. When created, an occurrence is said to have been instantiated , and both the creation process and the result of creation are called instantiation .
Individuals (instances) are the basic, "ground level" components of an ontology. The individuals in an ontology may include concrete objects such as people, animals, tables, automobiles, molecules, and planets, as well as abstract individuals such as numbers and words (although there are differences of opinion as to whether numbers and words are classes or individuals).
Objects can contain other objects in their instance variables; this is known as object composition. For example, an object in the Employee class might contain (either directly or through a pointer) an object in the Address class, in addition to its own instance variables like "first_name" and "position".
As an instance of a class, an object is constructed from a class via instantiation. Memory is allocated and initialized for the object state and a reference to the object is provided to consuming code. The object is usable until it is destroyed – its state memory is de-allocated.
Instance (computer science), referring to any running process or to an object as an instance of a class Table instance (or database instance), a concept in database design; see Row (database) Creation of an object (a location in memory having a value and possibly referenced by an identifier)
In object-oriented programming, the singleton pattern is a software design pattern that restricts the instantiation of a class to a singular instance. It is one of the well-known "Gang of Four" design patterns, which describe how to solve recurring problems in object-oriented software. [1]
In software development, an object is an entity that has state, behavior, and identity. [ 1 ] : 78 An object can model some part of reality or can be an invention of the design process whose collaborations with other such objects serve as the mechanisms that provide some higher-level behavior.
Instance variables are properties of that object. All instances of a class have their own copies of instance variables, even if the value is the same from one object to another. One class instance can change values of its instance variables without affecting all other instances. A class may have both instance variables and class variables.