While programming, you'll discover that you use certain pieces of code over and over, either within a script or in several scripts. Instead of writing that code over and over you can create a function and place those routines in it. This will save you time and make programming easier, especially as websites become more complex. Another advantage of a function is that it executes wherever and whenever you call it, in the same way that print() displays text.

User Defined Functions

The syntax to create a user defined function is:

function function_name(){

//statements here

}

You use the same naming conventions as you do for variables, without the dollar sign. Another rule to remember is to not use spaces when giving a name to a function. Otherwise it will be interpreted as two different words which will result in an error message. Use an underscore instead. Also, as a matter of good coding practice, it is good to give a representative name to a function. For example, set_name() would be a better function name than name1().

There are no limits as to how many statements can be included in the function.  A function must include all the required elements, which are:

• Function name
  
• Opening and closing parentheses - ()
  
• Opening and closing braces - {}
  
• Statements

The actual formatting of the function itself is not important, as long as the above elements are included. You call the function by its name to execute it.

function_name();

The above will cause the statements in the function to be executed.

Let's create a function that generates a random password.

We will call the function randpass():

Script:createrndpass.php

<?

function randpass()

 $chars = "1234567890abcdefGHIJKLMNOPQRSTUVWxyzABCDEF
ghijklmnopqrstuvwXYZ1234567890";

 $thepass = '';

 for($i=0;$i<7;$i++)

 {

  $thepass .= $chars{rand() % 39};

 }

 return $thepass;

}

//to use the function

$password=randpass();

?>

The above function creates a password with random numbers and letters. The $chars variable contains letters and numbers that are mixed up. The content of that variable is then randomized with the rnd() function and a result is returned in the $thepass variable.

The "return $thepass;" part of the function returns the function result to whatever variable you want it in. Therefore to run this function, all we need to do is:

$password =randpass();