what is the error: number of pence

[lse123]

what is the error: number of pence

given cents amount $x get number of coins the min can subdivided...
<?php
// File: example9-9.php

$x = 579;
$a200=0;
$a100=0;
$a50=0;
$a20=0;
$a10=0;
$a5=0;
$a2=0;
$a1=0;

$x1=1;
while ($x1<8) {


switch (true) {
case ($x>=200):
$a200=$x/200-($x%200)/200;
break;
case ($x>=100):
$a100=$x/100-($x%100)/100;
break;
case ($x>=50):
$a50=$x/50-($x%50)/50;
break;
case ($x>=20):
$a20=$x/20-($x%20)/20;
break;
case ($x>=10):
$a10=$x/10-($x%10)/10;
break;
case ($x>=5):
$a5=$x/5-($x%5)/5;
break;
case ($x>=2):
$a2=$x/2-($x%2)/2;
break;
default:
$a1=$x;
break;
}

$x1++ ;

}
echo $a200."x200<br />";
echo $a100."x100<br />";
echo $a50."x50<br />";
echo $a20."x20<br />";
echo $a10."x10<br />";
echo $a5."x5<br />";
echo $a2."x2<br />";
echo $a1."x1<br />";
?>

[lse123]

//problem self fixed...

switch (true) {
case ($x>=200):
$a200=$x/200-($x%200)/200;
$x-=$a200*200;
break;
case ($x>=100):
$a100=$x/100-($x%100)/100;
$x-=$a100*100;
break;
case ($x>=50):
$a50=$x/50-($x%50)/50;
$x-=$a50*50;
break;
case ($x>=20):
$a20=$x/20-($x%20)/20;
$x-=$a20*20;
break;
case ($x>=10):
$a10=$x/10-($x%10)/10;
$x-=$a10*10;
break;
case ($x>=5):
$a5=$x/5-($x%5)/5;
$x-=$a5*5;
break;
case ($x>=2):
$a2=$x/2-($x%2)/2;
$x-=$a2*2;
break;
default:
$a1=$x;
break;
}