PHP binary search (array)

//二分查找（数组里查找某个元素）  
function bin_sch($array,  $low, $high, $k){
    
      
   if ( $low <= $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;  
}