//+------------------------------------------------------------------+
//|                                             Balance of Power.mq5 |
//|                                           Copyright 2012, RoboFx |
//|                                            http://www.robofx.org |
//+------------------------------------------------------------------+
#property copyright "Copyright 2012, RoboFx"
#property link      "http://www.robofx.org"
#property version   "1.00"

#property indicator_separate_window
#property indicator_buffers 2
#property indicator_plots   1
//--- plot BoP
#property indicator_label1  "BOP"
#property indicator_type1   DRAW_COLOR_HISTOGRAM
#property indicator_color1  clrSteelBlue,C'0,0,0'
#property indicator_style1  STYLE_SOLID
#property indicator_width1  2

#include <MovingAverages.mqh>    //--- include moving averages methods

input int BOP_Period = 14;       //--- smoothing period

//--- indicator buffers
double         Buffer1[];        //--- raw data buffer
double         BOP[];            //--- main indicator buffer
//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int OnInit()
{
   //--- setting dynamic arrays as indicator buffers 
   SetIndexBuffer(0,BOP,INDICATOR_DATA);
   SetIndexBuffer(1,Buffer1,INDICATOR_CALCULATIONS);
   
   //--- setting the accuracy for indicator values 
   IndicatorSetInteger(INDICATOR_DIGITS,_Digits); 
   
   // --- setting the indicator name to be displayed in a separate subwindow
   IndicatorSetString(INDICATOR_SHORTNAME,"Balance of Power ("+string(BOP_Period)+")");   
//---
   return(0);
}
//+------------------------------------------------------------------+
//| 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[])
{
//---
   int start;
   
   //--- check for data
   if(rates_total < BOP_Period) return(0);
      
   //--- calculations of the starting number limit for the bar recalculation loop
   //--- recalculate the last bar 
   if(prev_calculated > 1) start = prev_calculated-1;
   else
   {
      start = 1;
   }
   
   //--- main indicator calculation loop 
   for(int i=start;i<rates_total && !IsStopped();i++)
   {
      //--- avoid zero divide problem in case high == low
      if((high[i]-low[i]) > 0.0) 
      {
         //--- calculate raw balance of power for the i-th bar
         Buffer1[i] = (close[i]-open[i])/(high[i]-low[i]);
      }
      else Buffer1[i] = 0;
   }
   
   // --- smoothing the indicator data using simple moving average
   SimpleMAOnBuffer(rates_total,prev_calculated,0,BOP_Period,Buffer1,BOP);
   
//--- return value of prev_calculated for next call
   return(rates_total);
}
//+------------------------------------------------------------------+