（php）生成任意进制N个字符

今天正好在用php写项目，刚好最近在学汇编，就用php随便写个了生成任意进制N个字符(仅限单个字符)，代码比较糙，还没来得急优化。回头用c++优化下再贴出来。

<?php

function createNext($str,$arr){
    
    $tmpStr = '';
    $isAdd = false;

    for($i = strlen($str)-1;$i>=0;$i--){

        $char = substr($str,$i,1);


        if($i===strlen($str)-1){
            foreach ($arr as $key => $value) {              
                if($value === $char){   
                    if($key+1 < count($arr)){
                        $tmpStr = $arr[$key+1].$tmpStr;                     
                    }else{
                        $tmpStr = $arr[0].$tmpStr;                  
                        $isAdd = true;
                    }               
                }
            }
        }else{
            if($isAdd){
                foreach ($arr as $key => $value) {              
                    if($value === $char){

                        if($key+1 < count($arr)){
                            $tmpStr = $arr[$key+1].$tmpStr;
                            $isAdd = false;
                        }else{
                            $tmpStr = $arr[0].$tmpStr;  
                            $isAdd = true;
                        }                   
                    }
                }
            }else{
                $tmpStr = $char.$tmpStr;
            }
        }   
    }

    if($isAdd){
        $tmpStr = $arr[1].$tmpStr;
    }
    return $tmpStr;
}

$arr      = ['0','1','2','3','4','5','6','7','8','9'];
$arr      = ['0','1','2','3','4','5'];
$arr      = ['a','b','c','d','e'];


$res      = createNext('abc',$arr);

$firstStr = $arr[0];
$total    = 155;
echo $firstStr ." ";

for ($i=0; $i < $total; $i++) {
    $res = createNext($firstStr,$arr);
    $firstStr = $res;
    echo $firstStr." ";
}

echo "\n";



?>

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