//+------------------------------------------------------------------+
//|                                                          ROC.mq4 |
//|                                    Copyright © 2006, Robert Hill |
//|                                                                  |
//+------------------------------------------------------------------+
#property  copyright "Copyright © 2006, Robert Hill"
//---- indicator settings
#property  indicator_separate_window
#property  indicator_buffers 1
#property  indicator_color1  Red
//---- indicator parameters
extern int RPeriod=10;
extern bool UsePercent = false;

//---- indicator buffers
double     RateOfChange[];

//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int init()
  {
//---- drawing settings
   SetIndexStyle(0,DRAW_LINE);
   SetIndexDrawBegin(0,RPeriod);
   IndicatorDigits(MarketInfo(Symbol(),MODE_DIGITS)+1);
//---- indicator buffers mapping
   if(!SetIndexBuffer(0,RateOfChange))
      Print("cannot set indicator buffers!");
//---- name for DataWindow and indicator subwindow label
   IndicatorShortName("ROC("+RPeriod+")");
   SetIndexLabel(0,"ROC");
//---- initialization done
   return(0);
  }
//+------------------------------------------------------------------+
//| Moving Averages Convergence/Divergence                           |
//+------------------------------------------------------------------+
int start()
  {
   int limit;
   double ROC, CurrentClose, PrevClose;
   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;
//---- ROC calculation
   for(int i=0; i<limit; i++)
   {
      CurrentClose = iClose(NULL,0,i);
      PrevClose = iClose(NULL,0,i+RPeriod);
      ROC=CurrentClose-PrevClose;
      if (UsePercent)
      {
        RateOfChange[i] = 100 * ROC / PrevClose; 
      }
      else
      {
        RateOfChange[i] = ROC;
      }
   }
      
//---- done
   return(0);
  }