//+------------------------------------------------------------------+
//|                                                        Bands.mq4 |
//|                      Copyright © 2005, MetaQuotes Software Corp. |
//|                                       http://www.metaquotes.net/ |
//+------------------------------------------------------------------+
#property copyright "Copyright © 2005, MetaQuotes Software Corp."
#property link      "http://www.metaquotes.net/"

#property indicator_chart_window
//#property indicator_buffers 3
#property indicator_buffers 2
#property indicator_color1 Blue
#property indicator_color2 Green
//#property indicator_color3 Red
//---- indicator parameters
extern int    TrailingStop = 20;

//---- buffers
double UpperBuffer[];
double LowerBuffer[];
//double ExitBuffer[];
//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int init()
  {
//---- indicators
   SetIndexStyle(0,DRAW_LINE);
   SetIndexBuffer(0,UpperBuffer);
   SetIndexStyle(1,DRAW_LINE);
   SetIndexBuffer(1,LowerBuffer);
   //SetIndexStyle(2,DRAW_ARROW);
   //SetIndexArrow(2,251);
   //SetIndexBuffer(2,ExitBuffer);
//----
   SetIndexDrawBegin(0,1);
   SetIndexDrawBegin(1,1);
//----
   return(0);
  }
//+------------------------------------------------------------------+
//| Bollinger Bands                                                  |
//+------------------------------------------------------------------+
int start()
  {
   int    i,k,counted_bars=IndicatorCounted();
   double uppertemp, lowertemp;
//----
   if(Bars<=1) return(0);
//---- initial zero
   if(counted_bars<1)
      for(i=1;i<=1;i++)
        {
         UpperBuffer[Bars-i]=EMPTY_VALUE;
         LowerBuffer[Bars-i]=EMPTY_VALUE;
        }
//----
   i=Bars;
   
   if(counted_bars>0) i=Bars-counted_bars-1;
   while(i>=0)
     {      

      uppertemp = Low[i+1] + TrailingStop*Point;
      if (uppertemp < UpperBuffer[i+1] || (UpperBuffer[i+1] == EMPTY_VALUE && High[i] < High[i+1]))  
         UpperBuffer[i]= uppertemp;
      else
         UpperBuffer[i] = UpperBuffer[i+1];    
              
      if(UpperBuffer[i] != EMPTY_VALUE && High[i] > UpperBuffer[i])
      {
         UpperBuffer[i] = EMPTY_VALUE;
         //ExitBuffer[i] = High[i];
      }
      
      
      lowertemp = High[i+1]-TrailingStop*Point;
      if (lowertemp > LowerBuffer[i+1] || (LowerBuffer[i+1] == EMPTY_VALUE && Low[i] > Low[i+1]))  
         LowerBuffer[i]=lowertemp;
      else
         LowerBuffer[i] = LowerBuffer[i+1];         
      
      if (LowerBuffer[i] != EMPTY_VALUE && Low[i] < LowerBuffer[i])
      {
         LowerBuffer[i] = EMPTY_VALUE;
         //ExitBuffer[i] = Low[i];
      }
      

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