Question

I have a recursive function that is supposed to print the contents of a directory. Here is the code

function dirs($dir, $tab) {
    $d = opendir($dir);
        while ( ($name = readdir($d)) !== false ) {
            if ( $name == "." or $name == ".." ) continue;
            if ( is_dir($dir . '/' . $name) ) {
                echo "<b>" . $tab . "[$name]</b><br>";
                $tab .= "-";
                dirs($dir . '/' . $name, $tab);
            }
            else {
                echo $tab . $name . '<br>';
            }
        }
        closedir($d);
}
dirs("C:/php5", "");

The output for this function wuld be like that ([extras] is empty directoty):

[dev]
-php5ts.lib
-[ext]
--php_bz2.dll
--php_curl.dll
--php_enchant.dll
--php_exif.dll
--etc.
--[extras]
---glib-2.dll
---gmodule-2.dll
---icudt.dll
---icudt46.dll
---icuin.dll
---etc.

but not like that

[dev]
-php5ts.lib
[ext]
-php_bz2.dll
-php_curl.dll
-php_enchant.dll
-php_exif.dll
-etc.
[extras]
glib-2.dll
gmodule-2.dll
icudt.dll
icudt46.dll
etc.

The question is why does “$tab” behave as a global variable and not as a local one?

Thanks in advance.

Answer 1

The problem is that you are actually re-assigning the value of the local copy of $tab, whereas what you actually want to be doing is passing $tab.'.' to the next iteration.

Because you have re-assigned it, it will continue to have the new value in the outer iteration after the inner iteration has executed.

Change:

$tab .= "-";
dirs($dir . '/' . $name, $tab);

to simply:

dirs($dir . '/' . $name, $tab . '-');