Cameron Garnett/Testpage9

PHP

Super Quick PHP Tutorial

Introduction | Basic Syntax | Sending Data to the Browser | Comments | Variables | Strings | Functions | Quotes | Debugging | Form

Learning Objectives By the end of this page you will know what a function is and how to write them using php code.

Functions

• A function is a block of statements that can be used repeatedly in a program.
  
• A function name can start with a letter or underscore (not a number).
  
• Give the function a name that reflects what the function does!
  

Example This is a basic skeleton of a function. function functionName() { code to be executed; }

PHP has more than 1000 built-in functions. If you don't think that is enough then you can create your own.

User Defined Functions
To create a user defined function in PHP you need to start with the word function.
In this first example I will create a function called displaystring(). The first curly bracket indicates the start of the code and the second curly bracket indicates the end of the function. Very similar to javascript.

Example <?php function displaystring() { echo "Today I went to the Zoo!"; } displaystring(); // calls the function. The output will be Today I went to the Zoo! ?>

In the next example to get a function to return a sum use the return statement. The $x and the $y inside the brackets are parameters.

Example <?php function sum($x, $y) { $z = $x + $y; return $z; } echo "4 + 6 = " . sum(4,6) . "; echo "8 + 12 = " . sum(8,12) . "; echo "3 + 4 = " . sum(3,4) . "; ?>

Activity Write the previous code into notepad++ and experiment with the format of functions.