$test_array = array (- 98, - 10, 0, 5, 6, 23, 98, 235 );
    $index1 = bin_sch ( $test_array, 0, 8, - 98 );
    echo 'find index:' . $index1;
    //二分查找
    function bin_sch($array, $low, $high, $k) {
        if ($low <= $high && count ( $array ) >= $high) {
            $mid = intval ( ($low + $high) / 2 );
            if ($array [$mid] == $k) {
                return $mid;
            } elseif ($k < $array [$mid]) {
                return bin_sch ( $array, $low, $mid - 1, $k );
            } else {
                return bin_sch ( $array, $mid + 1, $high, $k );
            }
        }
        return - 1;
    }
//顺序查找（数组里查找某个元素）
function seq_sch($array, $n, $k){
      $array[$n] = $k;   //防止溢出
      for($i=0; $i<$n; $i++){
          if($array[$i]==$k){
              break;
          }
      }
      if ($i<$n){
          return $i;
      }else{
          return -1;
      }
}