So what exactly IS object oriented programming? Easy question to ask, but a hard one to answer in just a sentence or two. Let's try.
In an object oriented scenario, you group together all the pieces of code that relate to a certain type of data. That code grouping will be called a class and it will usually be kept in a separate file to your main programs, so that you can write a whole suite of programs that handle the same data in different ways without having to keep re-writing the low level code.
For example, this Blog might be using an "entry" class (a class is the name given to the bundle of code that relates to a type of data) so that the logic I use when I write each day is shared with the logic used to generate the pages you see when you read it on our site, and is also shared with the logic that's use if anyone calls up an XML feed.
This isn't an easy way to start writing a small and simple program, but it's great when you expand your applications. You don't have to re-invent the wheel ... and if you change the internals of a class, all your applications will just keep on running provided that you keep the calls to the class compatible with the previous ones. In other words, it's a great way of cutting maintenance costs too.
A language is described as "An object oriented language" if it has a number of extra features that weren't in languages such as Fortran, Algol and C (on which I cut my teeth) and which facilitate programming in the OO way. OO has its whole world of extra concepts and buzzwords, but to bring them all up here on a horse's mouth entry would take me beyond my challenge of telling you what OO is about in just a short item. Longer articles (part of our training notes) may be
downloaded from our training notes site.
(written 2005-11-27, updated 2006-06-05)
Associated topics are indexed under
Q906 - Object Orientation and General technical topics - Object Orientation: Individual Objects [4021] Spike solution, refactored and reusable, Python - Example - (2013-02-28)
[3721] Naming blocks of code, structures and Object Orientation - efficient coding in manageable chunks - (2012-05-06)
[3436] Moving from scripting to Object Orientation in Python - (2011-09-13)
[2651] Calculation within objects - early, last minute, or cached? - (2010-02-26)
[2393] A first demonstration of OO, including polymorphism - (2009-09-04)
[2173] Basic OO principles - (2009-05-11)
[2171] Cleaning up redundant objects - (2009-05-11)
[1925] Introduction to Object Oriented Programming - (2008-12-06)
[1864] Object Oriented Perl - First Steps - (2008-11-01)
[1543] Learning Object Oriented Principles (and perhaps Java) - (2008-02-17)
[227] Bellringing and Programming and Objects and Perl - (2005-02-25)
Q907 - Object Orientation and General technical topics - Object Orientation: Design Techniques [3978] Teaching OO - how to avoid lots of window switching early on - (2013-01-17)
[3928] Storing your intermediate data - what format should you you choose? - (2012-11-20)
[3887] Inheritance, Composition and Associated objects - when to use which - Python example - (2012-10-10)
[3878] From Structured to Object Oriented Programming. - (2012-10-02)
[3844] Rooms ready for guests - each time, every time, thanks to good system design - (2012-08-20)
[3798] When you should use Object Orientation even in a short program - Python example - (2012-07-06)
[3763] Spike solutions and refactoring - a Python example - (2012-06-13)
[3760] Why you should use objects even for short data manipulation programs in Ruby - (2012-06-10)
[3607] Designing your application - using UML techniques - (2012-02-11)
[3454] Your PHP website - how to factor and refactor to reduce growing pains - (2011-09-24)
[3260] Ruby - a training example that puts many language elements together to demonstrate the whole - (2011-04-23)
[3085] Object Oriented Programming for Structured Programmers - conversion training - (2010-12-14)
[3063] Comments in and on Perl - a case for extreme OO programming - (2010-11-21)
[2977] What is a factory method and why use one? - Example in Ruby - (2010-09-30)
[2953] Turning an exercise into the real thing with extreme programming - (2010-09-11)
[2889] Should Python classes each be in their own file? - (2010-07-27)
[2878] Program for reliability and efficiency - do not duplicate, but rather share and re-use - (2010-07-19)
[2865] Relationships between Java classes - inheritance, packaging and others - (2010-07-10)
[2785] The Light bulb moment when people see how Object Orientation works in real use - (2010-05-28)
[2747] Containment, Associative Objects, Inheritance, packages and modules - (2010-04-30)
[2741] What is a factory? - (2010-04-26)
[2717] The Multiple Inheritance Conundrum, interfaces and mixins - (2010-04-11)
[2523] Plan your application before you start - (2009-12-02)
[2501] Simples - (2009-11-12)
[2380] Object Oriented programming - a practical design example - (2009-08-27)
[2327] Planning! - (2009-08-08)
[2170] Designing a heirarcy of classes - getting inheritance right - (2009-05-11)
[2169] When should I use OO techniques? - (2009-05-11)
[1538] Teaching Object Oriented Java with Students and Ice Cream - (2008-02-12)
[1528] Object Oriented Tcl - (2008-02-02)
[1435] Object Oriented Programming in Perl - Course - (2007-11-18)
[1224] Object Relation Mapping (ORM) - (2007-06-09)
[1217] What are factory and singleton classes? - (2007-06-04)
[1047] Maintainable code - some positive advice - (2007-01-21)
[836] Build on what you already have with OO - (2006-08-17)
[831] Comparison of Object Oriented Philosophy - Python, Java, C++, Perl - (2006-08-13)
[747] The Fag Packet Design Methodology - (2006-06-06)
[656] Think about your design even if you don't use full UML - (2006-03-24)
[534] Design - one name, one action - (2005-12-19)
[236] Tapping in on resources - (2005-03-05)
[80] OO - real benefits - (2004-10-09)
5431
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