Classes and Functions in PHP: Simple Tutorial for everyone

Classes and Functions in PHP: Simple Tutorial for everyone

A class is a function of PHP that has its roots in object oriented programming. The ability to use classes in PHP has been increasing with later versions. If you want to add the power of classes to your PHP programming, keep reading.

Continuing our PHP functions article, we move on to creating classes. Let me say right at the start that you can write perfectly effective and useful PHP code without creating classes or going into object oriented programming. Another thing is that PHP, at its core, is not an object oriented language. This is because PHP was built from the C language, which is at its core a procedural language, rather than a methodical one. However, object oriented programming can be very powerful and PHP programmers are increasingly taking advantage of these capabilities, which have been greatly expanded since PHP4.

What is a class?

A class is a collection of variables and functions that serves a common purpose. It gives you the ability to think about real world objects and translate them into code. For example, let's try to describe a car. The class "car" might have variables: $name_of_car, $wheels, $steeringwheel, $windscreen, $lights, $pedals and $brakes. The functions of a car might include Turnleft(),Turnright() and Accelerate(). The function "Accelerate()" might take arguments such as $increase_speed. Now, all of the above describes a car and what a car does in both real terms and in code.

Now you might ask, couldn't this be done with regular functions and variables? Yes, it could, especially if you were talking about one car. But if you are talking about more than one car, then it would be impossible to keep up with all the various variables and functions associated with multiple cars. This is where classes become very useful, because classes bring all those variables and functions under one name. In this case, it's an object named "car." Now if you have more than one car, all you have to do is instantiate that object. The term instantiate basically means making a copy of the object. The new copy will have all the variables and functions of the original object available to it. You can include the class in any script that you create; the class will work the same.

Let me sound a cautionary note. Although OOP makes coding easier and more portable, the objects' execution time is less efficient than writing straight code. And while OOP speeds up project development drastically, more often than not, it produces less customized and slower applications. So, be aware of these pitfalls when choosing to use OOP.

OOP is arguably difficult to learn, so in this article I am going to use very simple examples to demonstrate how to use OOP. This should help new users grasp the concepts easily. Also, because OOP is such a huge topic I will only deal with the basics so as to give you the ability to easily learn the more advanced aspects of it.

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How-To: Upload a File in PHP?

How-To: Upload a File in PHP?


Lately I have seen a ton of questions on the message board about uploading files to the server. It seems as if this is an epidemic that needs to be cured. I have written a PHP class for file uploads which some members of the message board have used and it helped to simplify their lives. Today we will attempt to write our own highly customizable file upload class. Before we get started get yourself a soda and something to munch on because this might take a while. Ready....(pause for the gathering of goodies)..okay let's begin.

What is a class and why do I need one?

Well to put it simply a class is a series of functions that work hand and hand to create an outcome. The reason a class works so great with uploading files is because there are a ton of functions one could write that would all depend on each other's outcome before the final result can be determined. For this reason we write a class instead of 10 functions and taking the time to validate each one.

Another beauty of a class is you can call any of the features within the class that you wish. For instance, with this class there will be 'x' amount of functions, all playing their role in the outcome of the actual upload process. If you wish to use this class to only verify a file's size and not upload it to the server, well you can. If you just wanted to get the file's extension and validate it, you could. That is the beauty of a class. If set up properly, classes are artwork, not just heavy amounts of code.

For rest of the tutorial read here.