//+------------------------------------------------------------------+
//|                                                 LastNcandles.mq4 |
//|                                              John Charles Taylor |
//|                http://financialprogrammingservices.blogspot.com/ |
//+------------------------------------------------------------------+
#property copyright "John Charles Taylor"
#property link      "http://financialprogrammingservices.blogspot.com/"

#property indicator_chart_window
#property indicator_buffers 0

extern int   NumCandles = 20;
extern color BoxColor = DodgerBlue;

int init() {
   return(0);
}

string BoxName="LastNcandles";

int deinit() {
   ObjectDelete(BoxName);
   return(0);
}

datetime LastTime=0;

int start() {
   if(LastTime!=Time[0]) {
      LastTime=Time[0];
      
      DrawOrMoveBox(NumCandles);   
   }

   return(0);
}

void DrawOrMoveBox(int period) {
   ObjectCreate(BoxName,OBJ_RECTANGLE,0,0,0); // Benign error if already exists ...
   ObjectMove  (BoxName,0,Time[period-1],iHigh(NULL,0,iHighest(NULL,0,MODE_HIGH,period)));
   ObjectMove  (BoxName,1,Time[0],       iLow (NULL,0,iLowest (NULL,0,MODE_LOW, period)));
}