to_ind_Acceleration_Bands

//+------------------------------------------------------------------+
//|                                    to_ind_Acceleration_Bands.mq4 |
//|                                                                * |
//|                                                                * |
//+------------------------------------------------------------------+
#property copyright "http://dmffx.com"
#property link      "http://dmffx.com"

#property indicator_chart_window
#property indicator_buffers 3
#property indicator_color1 Red
#property indicator_color2 Red
#property indicator_color3 Red
//---- input parameters
extern double    Factor=2; 
extern int       smPeriod=20;
extern int       smMethod=0;
//---- buffers
double ExtMapBuffer1[];
double ExtMapBuffer2[];
double ExtMapBuffer3[];
double ExtMapBuffer4[];
double ExtMapBuffer5[];
double ExtMapBuffer6[];
//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int init()
  {
//---- indicators
   IndicatorBuffers(6);
   SetIndexStyle(0,DRAW_LINE);
   SetIndexBuffer(0,ExtMapBuffer1);
   SetIndexStyle(1,DRAW_LINE);
   SetIndexBuffer(1,ExtMapBuffer2);
   SetIndexStyle(2,DRAW_LINE);
   SetIndexBuffer(2,ExtMapBuffer6);   
   
   SetIndexBuffer(3,ExtMapBuffer3);
   SetIndexBuffer(4,ExtMapBuffer4);   
   SetIndexBuffer(5,ExtMapBuffer5);  
   
   SetIndexLabel(0,"AB Upper");
   SetIndexLabel(1,"AB Lower");   
   SetIndexLabel(2,"AB Central");     
//----
   return(0);
  }
//+------------------------------------------------------------------+
//| Custom indicator deinitialization function                       |
//+------------------------------------------------------------------+
int deinit()
  {
//----
   
//----
   return(0);
  }
//+------------------------------------------------------------------+
//| Custom indicator iteration function                              |
//+------------------------------------------------------------------+
int start()
  {
   int    limit=Bars-IndicatorCounted();   
   
   for(int i=limit-1;i>=0;i--){
      ExtMapBuffer3[i]=(High[i]*(1+Factor*((((High[i]-Low[i])/((High[i]+Low[i])/2))*1000)*0.001)));
      ExtMapBuffer4[i]=(Low[i]*(1-Factor*((((High[i]-Low[i])/((High[i]+Low[i])/2))*1000)*0.001)));
      ExtMapBuffer5[i]=(ExtMapBuffer3[i]+ExtMapBuffer4[i])/2;
   }
   
   for(i=limit-1;i>=0;i--){
      ExtMapBuffer1[i]=iMAOnArray(ExtMapBuffer3,0,smPeriod,0,smMethod,i);
      ExtMapBuffer2[i]=iMAOnArray(ExtMapBuffer4,0,smPeriod,0,smMethod,i);
      ExtMapBuffer6[i]=(ExtMapBuffer1[i]+ExtMapBuffer2[i])/2;
   }   

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