Proper way to declare a function in PHP?

Question

I am not really clear about declaring functions in php, so I will give this a try.

getselection();

function getselection($selection,$price)
{
global $getprice;
switch($selection)
{
  case1: case 1:
        echo "You chose lemondew <br />";
        $price=$getprice['lemondew'].'<br>';
        echo "The price:".$price;
    break;

Please let me know if I am doing this wrong, I want to do this the correct way; in addition, php.net has examples but they are kind of complex for a newb, I guess when I become proficient I will start using their documentation, thank you for not flaming.

Please provide links that might also help me clear this up?

Answer 1

Your example seems valid enough to me.

foo('bar');
function foo($myVar)
{
  echo $myVar
}
// Output: bar

See this link for more info on user-defined functions.

Answer 2

You got off to a reasonable start. Now all you need to do is remove the redundant case 1:, close your switch statement with a } and then close your function with another }. I assume the global array $getprice is defined in your code but not shown in the question.

Answer 3

it's good practice to declare functions before calling them. It'll prevent infrequent misbehavior from your code.

Answer 4

The sample is basically a valid function definition (meaning it runs, except for what Asaph mentions about closing braces), but doesn't follow best practices.

• Naming conventions: When a name consists of two or more words, use camelCase or underscores_to_delineate_words. Which one you use isn't important, so long as you're consistent. See also Alex's question about PHP naming conventions.
• Picking a good name: a "get" prefix denotes a "getter" or "accessor"; any method or function of the form "getThing" should return a thing and have no affects visible outside the function or object. The sample function might be better called "printSelection" or "printItem", since it prints the name and price of the item that was selected.
• Globals: Generally speaking, globals cause problems. One alternative is to use classes or objects: make the variable a static member of a class or an instance member of an object. Another alternative is to pass the data as an additional parameter to the function, though a function with too many parameters isn't very readable.
• Switches are very useful, but not always the best choice. In the sample, $selection could easily hold the name of an item rather than a number. This points to one alternative to using switches: use an index into an array (which, incidentally, is how it's done in Python). If the cases have the same code but vary in values used, arrays are the way to go. If you're using objects, then polymorphism is the way to go--but that's a topic unto itself.
• The $price parameter appears to serve no purpose. If you want your function to return the price, use a return statement.
• When you called the function, you neglected to pass any arguments. This will result in warnings and notices, but will run.