//+------------------------------------------------------------------+
//|                                              BBandWidthRatio.mq4 |
//|                                                             Maji |
//+------------------------------------------------------------------+
#property copyright "Maji"
#property link      "None"

#property indicator_separate_window
#property indicator_buffers 1
#property indicator_color1 Blue

//---- input parameters
extern int       BB_Period=20;
extern double    Deviation=2.0;

double buf1[];
//double buf2[];
//double buf3[];
//double buf4[];


//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int init()
  {
   SetIndexStyle(0, DRAW_LINE, EMPTY, 2);
   IndicatorDigits(MarketInfo(Symbol(), MODE_DIGITS));
   SetIndexDrawBegin(0,BB_Period);
   SetIndexLabel(0,"BBandWidthRatio");
   SetIndexBuffer(0, buf1);
   return(0);
  }
//+------------------------------------------------------------------+
//| Custom indicator deinitialization function                       |
//+------------------------------------------------------------------+
int deinit()
  {
//----
   
//----
   return(0);
  }
//+------------------------------------------------------------------+
//| Custom indicator iteration function                              |
//+------------------------------------------------------------------+
int start()
  {
   int i, j;
   double ave, sko, sum;
   int counted_bars=IndicatorCounted();
   double MA, Up, Dn;
   
   if(Bars<=BB_Period) return(0);
      
   i=Bars-BB_Period;
   if(counted_bars>BB_Period) i=Bars-counted_bars-1;
   

   if (Bars<=BB_Period) return;
   
   for (i=Bars-BB_Period; i>=0; i--) 
   {
//    buf2[i] = iMA(NULL,0,BB_Period,0,MODE_SMA,PRICE_CLOSE,i);
    MA = iMA(NULL,0,BB_Period,0,MODE_SMA,PRICE_CLOSE,i);
    sum = 0;
    for (j=0; j<BB_Period; j++) sum+=Close[i+j];
    ave = sum / BB_Period;
    sum = 0;
    for (j=0; j<BB_Period; j++) sum+=(Close[i+j]-ave)*(Close[i+j]-ave);
    sko = MathSqrt(sum / BB_Period);
//    buf4[i] = buf2[i]+(Deviation*sko);
//    buf3[i] = buf2[i]-(Deviation*sko);
    Up = MA+(Deviation*sko);
    Dn = MA-(Deviation*sko);
//    buf1[i] = 2*(Deviation*sko)/buf2[i];
    buf1[i] = 2*(Deviation*sko)/MA;
  
   }
  
    return(0);
  
  }
//+------------------------------------------------------------------+