Returning Values from User-Defined Functions | Sams Teach Yourself PHP, MySQL and Apache in 24 Hours

In the previous example, we output an amended string to the browser within the printBR() function. Sometimes, however, you will want a function to provide you with a value that you can work with yourself. If your function has transformed a string that you have provided, you may wish to get the amended string back so that you can pass it to other functions. A function can return a value using the return statement in conjunction with a value. The return statement stops the execution of the function and sends the value back to the calling code.

Listing 6.4 creates a function that returns the sum of two numbers.

Listing 6.4 A Function That Returns a Value

   1: <html>   2: <head>   3: <title>Listing 6.4</title>   4: </head>   5: <body>   6: <?php   7: function addNums( $firstnum, $secondnum ) {   8:     $result = $firstnum + $secondnum;   9:     return $result;  10: }  11: print addNums(3,5);  12: // will print "8"  13: ?>  14: </body>  15: </html>

Put these lines into a text file called addnums.php, and place this file in your Web server document root. When you access this script through your Web browser, it produces the following:

Notice in line 7 that addNums() should be called with two numeric arguments (line 11 shows those to be 3 and 5 in this case). These are stored in the variables $firstnum and $secondnum. Predictably, addNums() adds the numbers contained in these variables together and stores the result in a variable called $result.

The return statement can return a value or nothing at all. How we arrive at a value passed by return can vary. The value can be hard-coded:

 return 4;

It can be the result of an expression:

 return ( $a/$b );

It can be the value returned by yet another function call:

 return ( another_function( $an_argument ) );