problem using $$variable

[Anon]

Hi.
What's the problem in this code?? i think it shoud be ok, but i don't get the correct result. Why??!

<FORM NAME="user_data" action="<? echo $php_self?>">
<INPUT TYPE=TEXT NAME=name>

<INPUT TYPE=SUBMIT NAME=ins VALUE="subm">
</FORM>

<?php
function check_req($foo) {
echo $foo[0] . " = "; // print "name"
echo $$foo[0]; // PRINT "": WHY??
}

$bar[]=("name");
check_req($bar);
?>

I'm a newbie, then the error maybe very silly.
Thankyou for your help.

[Anon]

You've run into the classic problem of php not being sure what to do with an array and a variable variable (i.e. $$var).

Now, the following var could be interpreted in two ways by php.

print $$tmp[0];

either we replace $tmp with some value and parse, or we replace $tmp[0] with it's var and parse.

In PHP we use {} to tell the parser which we mean.

i.e. we either have ${$tmp[0]} or ${$tmp}[0]

$tmp[0]="test";
$test="goodbye";
print ${$tmp[0]}; would print "goodbye"

while

$tmp="test";
$test[0]="hello";
print ${$tmp}[0]; would print "hello"