Returning Values from User-Defined Functions

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:

 8 

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 ) ); 


Sams Teach Yourself PHP, MySQL and Apache in 24 Hours
Sams Teach Yourself PHP, MySQL and Apache in 24 Hours
ISBN: 067232489X
EAN: 2147483647
Year: 2005
Pages: 263

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