php foreach循环中使用引用时问题

<?php
$array=array('a','b','c','d');
foreach($array as $key=>$val){
    //do something
}
echo $val;//输出d
echo $kay;//输出3
$val='e';
print_r($array);//输出Array ( [0] => a [1] => b [2] => c [3] => d )
?>

<?php
$array=array('a','b','c','d');
foreach($array as $key=>&$val){//使用引用
    //do something
}
echo $val;//输出d
echo $kay;//输出3
$val='e';
print_r($array);//输出Array ( [0] => a [1] => b [2] => c [3] => e )
?>

<?php
setcookie("bar", "www", time() + 10, "/", "www.111cn.net");
setcookie("bar", "foo", time() + 10, "/", ".111cn.net");
?>

<?php
var_dump($_COOKIE);
?>

<?php
setcookie("bar", "foo", time() + 10, "/", ".111cn.net");
setcookie("bar", "www", time() + 10, "/", "www.111cn.net");
?>

if (isset($_SERVER['HTTP_COOKIE'])) var_dump($_SERVER['HTTP_COOKIE']);

<?php
    $query='你好';
    $resultsText='1 条与 "[QUERY]" 相关的搜索结果';
    $resultsText = str_replace("[QUERY]", htmlentities($query,ENT_COMPAT,'UTF-8'), $resultsText);
    header('content-type: text/html; charset=utf-8');
 
    print_r($resultsText);
?>

function __fgetcsv(& $handle, $length = null, $d = ',', $e = '"') {
     $d = preg_quote($d);
     $e = preg_quote($e);
     $_line = "";
     $eof=false;
     while ($eof != true) {
         $_line .= (empty ($length) ? fgets($handle) : fgets($handle, $length));
         $itemcnt = preg_match_all('/' . $e . '/', $_line, $dummy);
         if ($itemcnt % 2 == 0)
             $eof = true;
     }
     $_csv_line = preg_replace('/(?: |[ ])?$/', $d, trim($_line));
     $_csv_pattern = '/(' . $e . '[^' . $e . ']*(?:' . $e . $e . '[^' . $e . ']*)*' . $e . '|[^' . $d . ']*)' . $d . '/';
     preg_match_all($_csv_pattern, $_csv_line, $_csv_matches);
     $_csv_data = $_csv_matches[1];
     for ($_csv_i = 0; $_csv_i < count($_csv_data); $_csv_i++) {
         $_csv_data[$_csv_i] = preg_replace('/^' . $e . '(.*)' . $e . '$/s', '$1' , $_csv_data[$_csv_i]);
         $_csv_data[$_csv_i] = str_replace($e . $e, $e, $_csv_data[$_csv_i]);
     }
     return empty ($_line) ? false : $_csv_data;
}

print(chr(0xEF).chr(0xBB).chr(0xBF));

<?php
$now = gmdate("D, d M Y H:i:s");
header("Expires: Tue, 03 Jul 2001 06:00:00 GMT");
header("Cache-Control: max-age=0, no-cache, must-revalidate, proxy-revalidate");
header("Last-Modified: {$now} GMT");
 
// force download
header("Content-Type: application/force-download");
header("Content-Type: application/octet-stream");
header("Content-Type: application/download");
 
// disposition / encoding on response body
header("Content-Disposition: attachment;filename={$filename}");
header("Content-Transfer-Encoding: binary");
$items_data=array(
'0'=>array('title'=>'test test test1'),
'1'=>array('title'=>'test test test2'),
'2'=>array('title'=>'test test test3')
)
print(chr(0xEF).chr(0xBB).chr(0xBF));//设置utf-8 + bom ，处理汉字显示的乱码
echo array2csv($items_data);
 
function array2csv(array &$array)
{
   if (count($array) == 0) {
     return null;
   }
   ob_start();
   $df = fopen("php://output", 'w');
   fputcsv($df, array_keys(reset($array)));
   foreach ($array as $row) {
      fputcsv($df, $row);
   }
   fclose($df);
   return ob_get_clean();
}
?>