php数字转汉字代码(算法)

//将数字转换为汉字，比如1210转换为一千二百一十 
$num = "842105580";//九位数 
function del0($num) //去掉数字段前面的0 
{ 
return "".intval($num); 
} 
function n2c($x) //单个数字变汉字 
{ 
$arr_n = array("零","一","二","三","四","五","六","七","八","九","十"); 
return $arr_n[$x]; 
} 
function num_r($abcd) //读取数值（4位） 
{ 
$arr= array(); 
$str = ""; //读取后的汉字数值 
$flag = 0; //该位是否为零 
$flag_end = 1; //是否以“零”结尾 
$size_r = strlen($abcd); 
for($i=0; $i<$size_r; $i++) 
{ 
$arr[$i] = $abcd{$i}; 
} 
$arrlen = count($arr); 
for($j=0; $j<$arrlen; $j++) 
{ 
$ch = n2c($arr[$arrlen-1-$j]); //从后向前转汉字 
echo $ch; 
echo ""; 
if($ch == "零" && $flag == 0){ //如果是第一个零 
$flag = 1; //该位为零 
$str = $ch.$str; //加入汉字数值字符串 
continue; 
}elseif($ch == "零"){ //如果不是第一个零了 
continue; 
} 
$flag = 0; //该位不是零 
switch($j) { 
case 0: $str = $ch; $flag_end = 0; break; //第一位（末尾），没有以“零”结尾 
case 1: $str = $ch."十".$str; break; //第二位 
case 2: $str = $ch."百".$str; break; //第三位 
case 3: $str = $ch."千".$str; break; //第四位 
} 
} 
if($flag_end == 1) //如果以“零”结尾 
{ 
mb_internal_encoding("UTF-8"); 
$str = mb_substr($str, 0, mb_strlen($str)-1); //把“零”去掉 
} 
return $str; 
} 
function num2ch($num) //整体读取转换 
{ 
$num_real = del0($num);//去掉前面的“0” 
$numlen = strlen($num_real); 
echo "numlen=".$numlen.""; 
if($numlen >= 9)//如果满九位，读取“亿”位 
{ 
$y=substr($num_real, -9, 1); 
//echo $y; 
$wsbq = substr($num_real, -8, 4); 
$gsbq = substr($num_real, -4); 
$a = num_r(del0($gsbq)); 
$b = num_r(del0($wsbq))."万"; 
$c = num_r(del0($y))."亿"; 
}elseif($numlen <= 8 && $numlen >= 5) //如果大于等于“万” 
{ 
$wsbq = substr($num_real, 0, $numlen-4); 
$gsbq = substr($num_real, -4); 
$a = num_r(del0($gsbq)); 
$b = num_r(del0($wsbq))."万"; 
$c=""; 
}elseif($numlen <= 4) //如果小于等于“千” 
{ 
$gsbq = substr( $num_real, -$numlen); 
$a = num_r(del0($gsbq)); 
$b=""; 
$c=""; 
} 
$ch_num = $c.$b.$a; 
return $ch_num; 
} 
echo $num.""; //数字 
echo num2ch($num); //汉字 
echo ""; 
echo num2ch("1240");