Posted 8 months, 3 weeks ago at 8:48 pm. 2 comments
Hello,
A lot of people want to learn how to make applications. Mac OS X provides an easy way to do so. Every single (genuine) Apple Computer comes with XCode on it’s install disks. Using XCode and the Cocoa framework makes it easy to learn and make your own application. And it is how most major Mac OS software publishers do it. I have made a video tutorial to introduce you to XCode and the things you can do with it. Although the application is somewhat simple, it is necesary to learn with simple applications and gradually move on with increasingly more difficult apps.
I started learning c++ a while back but got deterred when I learned it takes 70 lines or so using the winapi just to make a blank window! A few days ago I learned about Qt. Its probably something everybody knows about but me. Anyways what it is, is a cross-platform application framework that makes GUIs easy. I’m just learning about it myself right now so I can’t really teach how to use it, however, Qt gives some good very documentaion here.
You can make a full c++ source file in less than 10 lines that will make a window with a button that reads “Hello world!”. I know this is a short post, but it is only because I want to get back to learning Qt myself! For all of you php lovers. Qt has php bindings which you can download here. You could even easily make a gui application using php. I haven’t tried it, but it sounds cool to experiment with!
Welcome to my first real article. In this post I will be discussing functions, specifically in PHP. I am assuming you know basic PHP syntax, but if you don’t, it is easy enough to learn on your own.
In PHP there are 2 ‘types’ of functions. There are the ones that are there by default, and then the ones that you, personally, create. The ones that are there by default are very basic, and fundamental. The ones you will soon learn how to create yourself accomplish things like cleaning up the code, condensing the code, avoiding redundancy, and making it easier to read all around.
Examples of default functions include: include(), echo(), print(), etc…
Custom functions are made up by you. Here is an example.
function sayHelloWorld(){
echo "Hello World!";
}
With that included into your script, you can now write just write
sayHelloWorld();
And it will output “Hello World!”
As you can see, this is in fact a lot neater. While this is a simple example, it shows the power of functions. Say you wrote about 100+ lines of code for a login script, you could just make it into one big function that looks like this…
function loginUser($username, $password){
//code
if('foo' == 'bar'){
return true;
}else{
return false;
}
}
Now in that example, you might have seen something I haven’t talked about. Arguments.
function loginUser($username, $password){
the two variabls separated by the comma are called arguments. This is how you talk to the code, and give in information to work with. In that example, for the function’s ‘blue print’ if you will, I’m saying that when I call the function, I will be providing it with those two variables in that format. So lets say I wanted to directly call this function, I would write loginUser('wildwobby', 'thisismypass');
And then, the function will replace all the instances of the $username with the value of wildwobby, and all instances of $password with the value of thisismypass.
The other thing you probably see is the return true;
return false;
While it doesn’t make sense in my example without any real code, you would set it up so the function returns true if in fact the login was successful and false if it wasn’t. This is how the function talks back to you. you could put it into an if statement, and if the login went successful, it will execute the script within the if statement. if(loginUser('wildwobby', 'thisismypass')){
echo "You have been logged in!";
}else{
echo "Sorry, there was a problem with the login.";
}
This concludes the introduction to functions. Hopefully you know enough to start playing with this new wonderful skill of yours. Don’t hesitate to comment and let me know what you thought. Also, be sure to play around with php trying a bunch of random stuff on your own as it is truly the way to learn how to program!
