Normalized Volume Oscillator

//+------------------------------------------------------------------+
//|                                 Normalized Volume Oscillator.mq4 |
//|                                                  Vadim Shumiloff |
//|                                                shumiloff@mail.ru |
//+------------------------------------------------------------------+
#property copyright "Vadim Shumiloff"
#property link      "shumiloff@mail.ru"

#property indicator_separate_window
#property indicator_buffers 5
#property indicator_color1 Blue   // Çàêðàñêà îòðèöàòåëüíûõ áàðîâ
#property indicator_color2 Green       // Çàêðàñêà áàðîâ 0 - 38.2
#property indicator_color3 Lime        // Çàêðàñêà áàðîâ 38.2 - 61.8
#property indicator_color4 Yellow      // Çàêðàñêà áàðîâ 61.8 - 100
#property indicator_color5 White       // Çàêðàñêà áàðîâ ñâûøå 100

#property indicator_width1 2  
#property indicator_width2 2  
#property indicator_width3 2  
#property indicator_width4 2  
#property indicator_width5 2  

extern int VolumePeriod = 10;

double VolBufferH1[];
double VolBufferH2[];
double VolBufferH3[];
double VolBufferH4[];
double VolBufferH5[];

int init()
  {
   string short_name;

   IndicatorBuffers(5);
   
   SetIndexBuffer(1, VolBufferH1);
   SetIndexStyle(0, DRAW_HISTOGRAM);
   SetIndexBuffer(0, VolBufferH1);
   SetIndexDrawBegin(0, VolBufferH1);

   SetIndexBuffer(2, VolBufferH2);
   SetIndexStyle(1, DRAW_HISTOGRAM);
   SetIndexBuffer(1, VolBufferH2);
   SetIndexDrawBegin(1, VolBufferH2);
  
   SetIndexBuffer(3, VolBufferH3);
   SetIndexStyle(2, DRAW_HISTOGRAM);
   SetIndexBuffer(2, VolBufferH3);
   SetIndexDrawBegin(2, VolBufferH3);

   SetIndexBuffer(4, VolBufferH4);
   SetIndexStyle(3, DRAW_HISTOGRAM);
   SetIndexBuffer(3, VolBufferH4);
   SetIndexDrawBegin(3, VolBufferH4);

   SetIndexBuffer(5, VolBufferH5);
   SetIndexStyle(4, DRAW_HISTOGRAM);
   SetIndexBuffer(4, VolBufferH5);
   SetIndexDrawBegin(4, VolBufferH5);

   short_name="NVO (" + VolumePeriod + ")";
   IndicatorShortName(short_name);
   SetIndexLabel(0, short_name);

   return(0);
  }

int start()
  {
   int counted_bars = IndicatorCounted();

   if (counted_bars < 1)
      for (int i = 1; i <= VolumePeriod; i++) 
      {
         VolBufferH1[Bars-i] = 0;
         VolBufferH2[Bars-i] = 0;
         VolBufferH3[Bars-i] = 0;
         VolBufferH4[Bars-i] = 0;
         VolBufferH5[Bars-i] = 0;
      }

   int limit = Bars - counted_bars;
   if (counted_bars > 0) limit++;
   double nvo = 0;
   
   for(i = 0; i < limit; i++)
   {
      VolBufferH1[i] = 0;
      VolBufferH2[i] = 0;
      VolBufferH3[i] = 0;
      VolBufferH4[i] = 0;
      VolBufferH5[i] = 0;
      
      nvo = NormalizedVolume(i)*100 - 100;
      
      if (nvo < 0)
      {
         VolBufferH1[i] = nvo;
      }
      else
      {
         if (nvo < 38.2)
         {
            VolBufferH2[i] = nvo;
         }
         else
         {
            if (nvo < 61.8)
            {
               VolBufferH3[i] = nvo;
            }
            else
            {
               if (nvo < 100)
               {
                  VolBufferH4[i] = nvo;
               }
               else VolBufferH5[i] = nvo;
            }
         }
      }
   }
   
   return(0);
  }

double NormalizedVolume(int i)
{
   double nv = 0;
   for (int j = i; j < (i+VolumePeriod); j++) nv = nv + Volume[j];
   nv = nv / VolumePeriod;
   return (Volume[i] / nv);
}