//compile//
//+------------------------------------------------------------------+
//|                                            AcceleratorArrows.mq4 |
//|                         Copyright © 2009, Robert Hill            |
//|                                                                  |
//| Written by Robert Hill for use with Accellerator History method  |
//| from thread at Forex Fatory                                      |
//+------------------------------------------------------------------+

#property copyright "Copyright © 2009, Robert Hill"

#property indicator_chart_window
#property indicator_buffers 2
#property indicator_color1 LawnGreen
#property indicator_color2 Red
#property indicator_width1  2
#property indicator_width2  2

extern int shift = 61;
extern bool OnlyNewArrows = false;

int myShift;
double UpArrow[];
double DownArrow[];

//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int init()
  {
//---- indicators
   SetIndexStyle(0, DRAW_ARROW, EMPTY);
   SetIndexArrow(0, 233);
   SetIndexBuffer(0, UpArrow);
   SetIndexStyle(1, DRAW_ARROW, EMPTY);
   SetIndexArrow(1, 234);
   SetIndexBuffer(1, DownArrow);
   
   myShift = MathAbs(shift);
   

//----
   return(0);
  }
//+------------------------------------------------------------------+
//| Custom indicator deinitialization function                       |
//+------------------------------------------------------------------+
int deinit()
  {
//---- 

//----
   return(0);
  }

//+------------------------------------------------------------------+
//| Custom indicator iteration function                              |
//+------------------------------------------------------------------+
int start() {
   int limit, i, counter;
   double acc_cur, acc_prev;
   double Range, AvgRange;
   int counted_bars=IndicatorCounted();
//---- check for possible errors
   if(counted_bars<0) return(-1);
//---- last counted bar will be recounted
   if(counted_bars>0) counted_bars--;

   limit=Bars-counted_bars;
   
//   for(i = 1; i <= limit; i++) {
   for(i = limit; i >=0; i--) {
   
      counter=i;
      Range=0;
      AvgRange=0;
      for (counter=i ;counter<=i+9;counter++)
      {
         AvgRange=AvgRange+MathAbs(High[counter]-Low[counter]);
      }
      Range=AvgRange/10;
       
      
      UpArrow[i] = 0;
      DownArrow[i] = 0;
      acc_cur = iAC(NULL, 0, i+myShift);
      acc_prev = iAC(NULL, 0, i+myShift+1);
      
      if (OnlyNewArrows)
      {
        if (acc_cur < 0 && acc_prev >= 0)
        {
          UpArrow[i] = Low[i] - Range*0.75;
        }
        else if (acc_cur >= 0 && acc_prev < 0)
        {
          DownArrow[i] = High[i] + Range*0.75;
        }
      }
      else
      {
        if (acc_cur < 0 )
        {
          UpArrow[i] = Low[i] - Range*0.75;
        }
        else if (acc_cur >= 0 )
        {
          DownArrow[i] = High[i] + Range*0.75;
        }
      }
      
   }

   return(0);
}