bool  ArraySetAsSeries(
   const void&  array[],    // array by reference
   bool         flag        // true denotes reverse order of indexing
   );

#property indicator_chart_window
#property indicator_buffers 1
//--- indicator buffers
double         NumerationBuffer[];
//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int OnInit()
  {
//--- indicator buffers mapping
   SetIndexBuffer(0,NumerationBuffer,INDICATOR_DATA);
//--- set buffer style
   SetIndexStyle(0,DRAW_LINE,STYLE_SOLID,1,CLR_NONE);
//--- set indexing for the buffer like in timeseries
   ArraySetAsSeries(NumerationBuffer,true);
//--- set accuracy of showing in DataWindow
   IndicatorSetInteger(INDICATOR_DIGITS,0);
//--- how the name of the indicator arry is displayed in DataWindow
   IndicatorShortName("Bar #");
//---
   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[])
  {
//---  we'll store the time of the current zero bar opening
   static datetime currentBarTimeOpen=0;
//--- revert access to array time[] - do it like in timeseries
   ArraySetAsSeries(time,true);
//--- If time of zero bar differs from the stored one
   if(currentBarTimeOpen!=time[0])
     {
     //--- enumerate all bars from the current to the chart depth
      for(int i=rates_total-1;i>=0;i--) NumerationBuffer[i]=i;
      currentBarTimeOpen=time[0];
     }
//--- return value of prev_calculated for next call
   return(rates_total);
  }