counter A B C

<pre>
<?php
//============= 65-90 (26)
$num=isset($_GET['n'])?$_GET['n']:53;

$cnum= counter_num($num,true );

echo "num:".$num." counter:".$cnum;
for ($i=2870;$i<3360;$i++){
    echo"<br>$i:".counter_num($i);
}
echo "<hr>";
$tmp='A';
echo ord($tmp)."\n".ord("Z");
/*
debug hanya digunakan apabila ingin melihat proses
sudah di uji pake nilai tinggi
*/
function counter_num($num0=0,$debug=false){
    $word='';
    if($num0==0) return null;
    $num=$num0-1;
    if($debug)echo "counter_num\t num:$num\n";

    do{
        $div = floor($num / 26);
        $mod = $num % 26;
        if($debug)echo "counter_num\t div:$div |mod:$mod\n";
        $i=$mod+65;
        $word.=chr($i);
        $num=$div;
    }while($div>26);

    if($num>0){
        if($debug)echo "counter_num\t $num ?\n";
        $i=$num+64;
        $word.=chr($i);
    }

    return strrev($word);
}