//+------------------------------------------------------------------+
//|                                                  HiLowPeriod.mq4 |
//|                                              Copyright 2021, AM2 |
//|                                      http://www.forexsystems.biz |
//+------------------------------------------------------------------+
#property copyright "Copyright 2021, AM2"
#property link      "http://www.forexsystems.biz"
#property version   "1.00"
#property strict
#property indicator_chart_window

#property indicator_buffers 2

extern int Num=300;
extern int Count=1111;

double up[];
double dn[];

//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int OnInit()
  {
//--- indicator buffers mapping
   SetIndexStyle(0,DRAW_LINE,0,2,Red);
   SetIndexBuffer(0,up);

   SetIndexStyle(1,DRAW_LINE,0,2,Blue);
   SetIndexBuffer(1,dn);

   Comment("");
//---
   return(INIT_SUCCEEDED);
  }
//+------------------------------------------------------------------+
//| Custom indicator iteration function                              |
//+------------------------------------------------------------------+
int OnCalculate(const int rates_total,
                const int prev_calculated,
                const datetime &time[],
                const double &open[],
                const double &high[],
                const double &low[],
                const double &close[],
                const long &tick_volume[],
                const long &volume[],
                const int &spread[])
  {
//---

   for(int i=0; i<Count; i++)
     {
      up[i]=high[iHighest(NULL,0,MODE_HIGH,Num,i)];
      dn[i]=low[iLowest(NULL,0,MODE_LOW,Num,i)];
     }

//--- return value of prev_calculated for next call
   return(rates_total);
  }
//+------------------------------------------------------------------+

   double hi1=high[iHighest(NULL,0,2,num,0)];
   double hi2=high[iHighest(NULL,0,2,count,0)];

   double lo1=low[iLowest(NULL,0,3,num,0)];
   double lo2=low[iLowest(NULL,0,3,count,count-num)];