Jump to navigation Jump to search “Object-oriented” redirects here. For a list of object-oriented programming log4j2 programmatic configuration, see List of object-oriented programming languages. Object-oriented programming uses objects, but not all of the associated techniques and structures are supported directly in languages that claim to support OOP.
Variables that can store information formatted in a small number of built-in data types like integers and alphanumeric characters. Modular programming support provides the ability to group procedures into files and modules for organizational purposes. Modules are namespaced so identifiers in one module will not be accidentally confused with a procedure or variable sharing the same name in another file or module. Languages that support object-oriented programming typically use inheritance for code reuse and extensibility in the form of either classes or prototypes. Objects sometimes correspond to things found in the real world. For example, a graphics program may have objects such as “circle”, “square”, “menu”. An online shopping system might have objects such as “shopping cart”, “customer”, and “product”.
Sometimes objects represent more abstract entities, like an object that represents an open file, or an object that provides the service of translating measurements from U. Objects are accessed somewhat like variables with complex internal structure, and in many languages are effectively pointers, serving as actual references to a single instance of said object in memory within a heap or stack. Object-oriented programming that uses classes is sometimes called class-based programming, while prototype-based programming does not typically use classes. As a result, a significantly different yet analogous terminology is used to define the concepts of object and instance. In some languages classes and objects can be composed using other concepts like traits and mixins. In class-based languages the classes are defined beforehand and the objects are instantiated based on the classes. In prototype-based languages the objects are the primary entities.
The prototype of an object is just another object to which the object is linked. New objects can be created based on already existing objects chosen as their prototype. It is the responsibility of the object, not any external code, to select the procedural code to execute in response to a method call, typically by looking up the method at run time in a table associated with the object. A method call is also known as message passing. Encapsulation is an object-oriented programming concept that binds together the data and functions that manipulate the data, and that keeps both safe from outside interference and misuse.
Data encapsulation led to the important OOP concept of data hiding. If a class does not allow calling code to access internal object data and permits access through methods only, this is a strong form of abstraction or information hiding known as encapsulation. Address class, in addition to its own instance variables like “first_name” and “position”. Languages that support classes almost always support inheritance. This allows classes to be arranged in a hierarchy that represents “is-a-type-of” relationships.