//+------------------------------------------------------------------+
//|                      Donchian Channels - Generalized version.mq4 |
//|                         Copyright © 2005, Luis Guilherme Damiani |
//|                                      http://www.damianifx.com.br |
//+------------------------------------------------------------------+
#property copyright "Copyright © 2005, Luis Guilherme Damiani"
#property link      "http://www.damianifx.com.br"
//----
#property indicator_chart_window
#property indicator_buffers 2
#property indicator_color1 Magenta
#property indicator_color2 SteelBlue
//---- input parameters
extern int       Periods=24;
extern int       Extremes=3;
extern int       Margins=-2;
extern int       Advance=0;
extern int       max_bars=700;
//---- buffers
double ExtMapBuffer1[];
double ExtMapBuffer2[];
//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int init()
  {
//---- indicators
   SetIndexStyle(0,DRAW_LINE,1,2);
   SetIndexBuffer(0,ExtMapBuffer1);
   SetIndexStyle(1,DRAW_LINE,1,2);
   SetIndexBuffer(1,ExtMapBuffer2);
//----
   IndicatorShortName("DoC("+Periods+")");
//----
   return(0);
  }
//+------------------------------------------------------------------+
//| Custor indicator deinitialization function                       |
//+------------------------------------------------------------------+
int deinit()
  {
//---- 
//----
   return(0);
  }
//+------------------------------------------------------------------+
//| Custom indicator iteration function                              |
//+------------------------------------------------------------------+
int start()
  {
   int    fixed_bars=IndicatorCounted();
//---- 
   //int shift=0;//, cnt(0), loopbegin(0);
   double smin=0, smax=0, SsMax=0, SsMin=0;
   //Variables : bar(0), prevbars(0), start(0), cs(0), prevcs(0),commodt(0);
   if(max_bars==0) max_bars=Bars;
//----
   for(int shift=0;shift< max_bars;shift++)
     {
      if (Extremes ==1)
        {
         SsMax=High[Highest(NULL,0,MODE_HIGH,Periods,shift)];
         SsMin=Low[Lowest(NULL,0,MODE_LOW,Periods,shift)];
        }
      else if (Extremes==3)
           {
            SsMax=(Open[Highest(NULL,0,MODE_OPEN,Periods,shift)]+High[Highest(NULL,0,MODE_HIGH,Periods,shift)])/2;
            SsMin=(Open[Lowest(NULL,0,MODE_OPEN,Periods,shift)]+Low[Lowest(NULL,0,MODE_LOW,Periods,shift)])/2;
           }
         else
           {
            SsMax=Open[Highest(NULL,0,MODE_OPEN,Periods,shift)];
            SsMin=Open[Lowest(NULL,0,MODE_OPEN,Periods,shift)];
           }
      smin=SsMin+(SsMax-SsMin)*Margins/100;
      smax=SsMax-(SsMax-SsMin)*Margins/100;
      ExtMapBuffer1[shift-Advance]=smin;
      ExtMapBuffer2[shift-Advance]=smax;
     }
//----
   return(0);
  }
//+------------------------------------------------------------------+