What is Object Oriented Programming (OOP)?

By Tony Marston
2007-01-30


Introduction
Quite often I see a question in a newsgroup or forum along the lines of: What is this thing called 'OOP'? What is so special about it? Why should I use it? How do I use it?. The person asking this type of question usually has experience of non-OO programming and wants to know the benefits of making the switch. Unfortunately most of the replies I have seen have been long on words but short on substance, full of airy-fairy, wishy-washy, meaningless phrases which are absolutely no use at all to man or beast.

Having created 1000's of programs using non-OO languages, and another 500+ using the OO features of PHP I feel more than qualified to add my own contribution to the melting pot. According to some OO 'purists' I am not qualified at all as I was not taught to do things 'their' way and I refuse to follow 'their' methods. My response to that accusation is that there is no such thing as 'only one true way' with OOP just as there is no such thing as 'only one true way' with religion. People tell me that my methods are wrong, but they are making a classic mistake. My methods cannot be wrong for the simple reason that they work, and anybody with more than two brain cells to rub together will tell you that something that works cannot be wrong just as something that does not work cannot be right. My methods are not wrong, they are simply different, and sometimes it is a willingness to adopt a different approach that separates the code monkeys from the engineers.

One reason why some people give totally useless answers is that it was what they were taught, and they do not have the intelligence to look beyond what they were taught. Another reason is that some of the explanations about OO are rather vague and can be interpreted in several ways, and if something is open to interpretation it is also open to a great deal of mis-interpretation. If you do not believe that there is widespread confusion as to what OO is and is not then take a look at Nobody Agrees On What OO Is. Even some of the basic terminology can mean different things to different people, as explained in Abstraction, Encapsulation, and Information Hiding. If these people cannot agree on the basic concepts of OOP, then how can they possibly agree on how those concepts may be implemented.

Tutorial Pages:
» Introduction
» What OOP is NOT
» What is an Object Oriented language?
» What OOP is
» The difference between OOP and non-OOP
» Practical Examples
» Conclusion
» References

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