PHP判断一个字符串是否是回文字符串
<?php
  function ishuiwen($str){
   $len=strlen($str);
   $l=1;
   $k=intval($len/2)+1;
     for($j=0;$j<$k;$j++){
       if (substr($str,$j,1)!=substr($str,$len-$j-1,1))
          {
   $l=0;
   break;
     }
    
   
  }
  if ($l==1)
  {
  return 1;
  }
  else
  {
  return -1; 
   }
  }
  
  $str=12321;
  echo ishuiwen($str);
?>




