Arrays and Functions

Hello all, Is it possible to increment and array inside of a function and then call the array out side of the funciton. While in side the function I am able to echo the array and see what I should see out side of the funtion! Would I need to use global???? <? function alpha($a1) {

        $a = $a1;
        for ($i=$a;$i<10;$i++) {
                $array1[$i] = $array1[$i] + 1;
                }

        return;
        };

for ($i=0;$i<10;$i++) {

        $array1[$i] = 0;
        };

alpha(0); ?> Hello world!!! <?

        for ($i=0;$i<10;$i++) {
                echo "<br>The number is :".$array1[$i];
                }

?>