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object

By Peter Loshin

What is an object?

In object-oriented programming (OOP), objects are the things you think about first in designing a program and they are also the units of code that are eventually derived from the process. In between, each object is made into a generic class of object, and even more generic classes are defined so that objects can share models and reuse the class definitions in their code. Each object is an instance of a particular class or subclass with the class's own methods or procedures and data variables. An object is what actually runs in the computer.

Characteristics of an object

All individual objects possess three basic characteristics -- identity, state and behavior. Understanding these characteristics is crucial to knowing how objects and object-oriented logic work.

Some of the things in programming that can be defined as objects include the following:

Objects can do things and can have things done to them. For example, a function or method object can be programmed to modify the contents of a data structure or variable object.

Object-based languages

Object-based languages support the full complement of features of object-oriented programming. These features are as follows:

Most modern programming languages are considered object-oriented languages, but some are more object-oriented than others, depending on how the OOP principles are implemented in the language and how they are used. Some languages that were originally designed as procedural programming languages have, over the years, had OOP features added.

Some of the most common languages that are considered to be object-oriented currently in use include the following:

Non-OOP languages include the following:

In general, modern programming languages support some or all OOP features while non-OOP languages tend to be older or more specialized.

Object-based languages

Programming languages that use encapsulation and state -- including object-oriented languages -- are known as object-based languages. This category includes all OOP languages as well as some other languages that do not fully implement the OOP model. Some well-known object-based languages include the following:

Many programming languages originated as object-based or even as non-object-based languages but added over the years features associated with OOP in some way. For example, early versions of Visual Basic and JavaScript lacked full object orientation but have added support since their introduction.

Benefits of using objects in programming

Using objects in programming has become commonplace, as most modern programming languages now support some or all of the principles of object-oriented programming. Some of the most important benefits of using objects in programming include the following:

That is not to say that programming with objects does not have a downside. Some of the disadvantages of using objects in programming include the following:

The differences between types of programming languages may not be as critical for simple programs, but for more complex programming projects there are differences that make one programming framework better than another.

Types of objects

Objects can be categorized based on what they do or how they work. Some of the most commonly used types of objects include the following:

These and other types of objects are based on design patterns, which represent repeatable solutions to common tasks or problems in programming. The patterns themselves are not objects but are used to develop objects that fulfill the functions of those patterns.

God objects are objects that break the rules by doing more than one thing. If you're still learning object- oriented programming, find out how to refactor the God object class antipattern. Otherwise, get started with this breakdown of object-oriented programming concepts.

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12 Apr 2022

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