Gold Spread of Williams

//+------------------------------------------------------------------+
//|                                                   GoldSpread.mq4 |
//|                      Copyright © 2009, C-4, All Rights Reserved. |
//|                                                   vs-box@mail.ru |
//+------------------------------------------------------------------+
#property copyright "Copyright © 2009, C-4, All Rights Reserved."
#property link      "vs-box@mail.ru"

#property indicator_separate_window
#property  indicator_buffers 1
#property  indicator_color1  Red
extern string symbol_name="DX_CONT";//Íàçâàíèå èíñòðóìåíòà èíäåêñà äîëëàðà, âûñòàâëÿåòñÿ âðó÷íóþ.

double GoldSpread[],
       SpreadDG[];

int init()
{
   IndicatorBuffers(2);
   SetIndexBuffer(0,GoldSpread);
   SetIndexBuffer(1,SpreadDG);
   IndicatorShortName("Gold Spread of Williams");
   SetLevelValue(0,0.0);
   SetLevelValue(1,0.3);
   SetLevelValue(2,-0.3);
   if(iTime(symbol_name,0,0)==0){
      Print("Óêàçàíî íåñóùåñòâóþùåå íàçâàíèå èíñòðóìåíòà. Äàëüíåéøåå îòîáðàæåíèå èíäèêàòîðà áóäåò íåâîçìîæíî.");
      Print("Ïðèñâîéòå ïåðåìåííîé symbol_name íàçâàíèå ñóùåñòâóþùåãî èíñòðóìåíòà(èíäåêñà äîëëàðà).");
   }
   return(0);
}

int start()
{
   if(iBars(symbol_name,0)==0)return(1);
   int limit,counted_bars;
   counted_bars=IndicatorCounted();
   limit=Bars-counted_bars;
   for(int i=0; i<limit; i++){
      SpreadDG[i]=iClose(symbol_name,0,i)-iClose(Symbol(),0,i);
   }
   for(i=0; i<limit; i++){
      GoldSpread[i]=(iMAOnArray(SpreadDG,Bars,21,0,MODE_SMA,i)-iMAOnArray(SpreadDG,Bars,3,0,MODE_SMA,i))/100;
   }
}