如何使用多个str_split文本字符行获得良好的结果

Question

在我的php代码中，我尝试从数据库中获取多个文本字符，并在每个结果输出中str_split。将USED添加到每个输出的结束行，并输出剩余的字符，我也尝试过：

 require("init.php"); 
 echo "<form action='reg.php' method='post'>
            <b>booking code:</b><br />
            <input type='text' name='book' size='17' /> 
            <input type='submit' name='login' maxlength='2' size='2' value='PRINT OUT' />
        </form>"; 

  if(isset($_POST["login"]))
  { 
      $book = mysqli_real_escape_string($conn, $_POST["book"]); 
      $sql = "SELECT `item_name` , `quantity` FROM `books` WHERE `book`='$book'"; $query = mysqli_query($conn, $sql); 
      while ($row1 = mysqli_fetch_array($query)) { 
        $d[] = $row1["item_name"]; 
        $v[] = $row1["quantity"]; 
        foreach($d as $r); 
        foreach($v as $ro); 
        $get = array(0 => array("yes" => $r, "no" => $ro)); 
        foreach ($get as $item) { 
           $getd = $item["yes"]; 
        } 
        $sql = mysqli_query($conn, "SELECT * FROM promo WHERE code='$getd' LIMIT 1"); 
        while ($row = mysqli_fetch_array($sql)) { 
           $type = $row["name"]; 
           $code = $row["recharge"]; 
           $deta = $row["details"]; 
           $logo = $row["logo"]; 
           $price = $row["price"]; 
           if(preg_match('/(xyz)/i', $type)) $type = "20"; 
           if(preg_match('/(log)/i', $type)) $type = "16"; 
        } 
        $id = $item["no"];  
        $result = str_split($code, $type); 
        $a = ""; 
        $c = "";
for($b = 0; $b<$id; $b++)
  {
    $a .= $result[$b];
}
$b = "USED";
for($bn = $id; $bn<sizeof($result); $bn++){
           $c .= $result[$bn];
        }
    echo $a.$b.$c;
}
}
}

并且我的所有结果输出代码都是不可知的，我说所有结果都是完整的结果输出，感谢您在我的解决方案中的时间和影响