//+------------------------------------------------------------------+
//|                                        Custom Moving Average.mq4 |
//|                      Copyright © 2004, MetaQuotes Software Corp. |
//|                                       http://www.metaquotes.net/ |
//+------------------------------------------------------------------+
#property copyright "Copyright © 2004, MetaQuotes Software Corp."
#property link      "http://www.metaquotes.net/"
#property indicator_chart_window
#property indicator_buffers 1
#property indicator_color1 Red
//---- indicator parameters
//---- forward declaration of input parameters with global scope.
extern int ExtPeriod=12;
extern int ExtType=0;
//---- indicator buffers
double     ExtMapBuffer[1];
//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int init()
  {
   string name="Unknown";
//---- drawing settings
   SetIndexStyle(0,DRAW_LINE);
   SetIndexDrawBegin(0,ExtPeriod);
   SetIndexDigits(5);
//---- indicator buffers mapping
   SetIndicatorArray(ExtMapBuffer,0);
//----
	switch(ExtType)
	  {
	   case 0: name="SMA"; break;
      case 1: name="EMA"; break;
      case 2: name="SMA"; break;
      case 3: name="LMA"; break;
     }
   IndicatorShortName(name+"("+ExtPeriod+")");
//---- initialization done
   return(0);
  }
//+------------------------------------------------------------------+
//| Moving Averages Convergence/Divergence                           |
//+------------------------------------------------------------------+
int start()
  {
   int limit;
   int counted_bars=IndicatorCounted();
//---- check for possible errors
   if(counted_bars<0) return(-1);
//---- last counted bar will be recounted
   if(counted_bars>0) counted_bars--;
   limit=Bars-counted_bars;
//---- calculate current moving average value
   switch(ExtType)
     {
      case 0: CalculateSMA(counted_bars);  break;
/*      case 1: CalculateEMA(counted_bars);  break;
      case 2: CalculateSMMA(counted_bars); break;
      case 3: CalculateLWMA(counted_bars); break; */
     }
/* 
//---- macd counted in the 1-st buffer
   for(int i=0; i<limit; i++)
      ind_buffer1[i]=iMA(NULL,0,FastEMA,0,MODE_EMA,PRICE_CLOSE,i)-iMA(NULL,0,SlowEMA,0,MODE_EMA,PRICE_CLOSE,i);
//---- signal line counted in the 2-nd buffer
   for(i=0; i<limit; i++)
      ind_buffer2[i]=iMAOnArray(ind_buffer1,Bars,SignalSMA,0,MODE_SMA,i);
      */
//---- done
   return(0);
  }
//+------------------------------------------------------------------+
//| Calculate Simple Moving Average                                  |
//+------------------------------------------------------------------+
void CalculateSMA(int counted_bars)
  {
   int    i,pos=Bars-counted_bars+1;
   double sum=0;
//---- initial accumulation
   for(i=1;i<ExtPeriod;i++) 
     {
      sum+=Close[pos];
      pos++;
     }
//---- main calculation loop
   pos=Bars-counted_bars;
   while(pos>=0)
     {
      sum+=Close[pos];
      ExtMapBuffer[pos]=sum/ExtPeriod;
	   sum-=Close[pos+ExtPeriod-1];
 	   pos--;
     }
//---- zero initial bars
   if(counted_bars<1)
     for(i=1;i<ExtPeriod;i++) ExtMapBuffer[Bars-i]=0;
  }
//+------------------------------------------------------------------+
//| Calculate Exponential Moving Average                             |
//+------------------------------------------------------------------+
/*
void CalculateEMA()
  {
   int    i;                  // index
   double value,prev;         // current and previous values
   double k=2/(1+ExtPeriod); // EMA coefficient
//----
   if(g_LoopBars<1 || g_LastBars!=Bars)   // full recalculation
   	 {
      prev=Close[Bars-1];
      i=1;
      //---- main calculation loop
      while(i<=Bars)
     	{
         value=prev+k*(Close[Bars-i]-prev);
         SetIndexValue(0,Bars-i,value);
         prev=value;
         g_LastPrev=prev;
         i++;
        }
      return;
     }
//---- fast mode
   SetIndexValue(0,0,g_LastPrev+k*(Close[0]-g_LastPrev));
//----
  }
//+------------------------------------------------------------------+
//| Calculate Smoothed Moving Average                                |
//+------------------------------------------------------------------+
void CalculateSMMA(int counted_bars)
  {
   int    i;
   double value,prev;
//---- full recalculation
   if(g_LoopBars<1 || g_LastBars!=Bars)
     {
      for(i=0;i<=ExtPeriod;i++) prev+=Close[Bars-i];
      i=ExtPeriod+1;
      //---- main calculation loop
      while(i<=Bars)
        {
         value=(prev*ExtPeriod-prev+Close[Bars-i])/ExtPeriod;
         prev=value;
         g_LastPrev=prev;
         SetIndexValue(0,Bars-i,value);
         i++;
        }
      return;
     }
//---- fast mode
   SetIndexValue(0,0,(g_LastPrev*ExtPeriod-g_LastPrev+Close[0])/ExtPeriod);
//----
  }
//+------------------------------------------------------------------+
//| Calculate Linear Weighted Moving Average                         |
//+------------------------------------------------------------------+
void CalculateLWMA(int counted_bars)
  {
   double  wsum=0;   // weghted sum
   double  lsum=0;   // linear sum
   int     i;        // common index
   int     weight=0; // weight sum
//---- full & optimized recalculation
   if(g_LoopBars<1 || g_LastBars!=Bars)
     {
      //---- calculate first point
      for(i=0;i<=ExtPeriod;i++)
        {
         wsum=wsum+Close[Bars-ExtPeriod+i]*(ExtPeriod-i);
         lsum=lsum+Close[Bars-ExtPeriod+i];
         weight+=(ExtPeriod-i);
        }
      //---- fast calculation of folowing points
      for(i=Bars-ExtPeriod-1;i>=0;i--)
        {
         wsum=wsum-lsum+Close[i]*ExtPeriod;
         lsum=lsum-Close[i+ExtPeriod];
         lsum=lsum+Close[i];
         SetIndexValue(0,i,wsum/weight);
         //---- store linear & weighted sums for fast calculation
         g_LastWSum=wsum;
         g_LastLSum=lsum;
        }
      return;
     }
//---- fast mode
   for(i=0;i<=ExtPeriod;i++) weight+=(ExtPeriod-i);
   wsum=g_LastWSum-g_LastLSum+Close[0]*ExtPeriod;
   SetIndexValue(0,0,wsum/weight);
//----
  } */
//+------------------------------------------------------------------+