Personalized EMA

[Andrei Boca]

Hi, i want to make an Ema with a difference source different from price_close price_open etc. I want to make ema with volume for example.

[Chad Magruder]

Write a custom indicator using EMA calculations on iVolume data. Should be easy... here is code for simple moving average of volume. 

Here is a link to the EMA formula: https://www.metatrader5.com/en/terminal/help/indicators/trend_indicators/ma

//+------------------------------------------------------------------+
//|                                                     VolumeMA.mq4 |
//|                                    Copyright 2019, Chad Magruder |
//+------------------------------------------------------------------+
#property copyright "Copyright 2019, Chad Magruder"
#property link      ""
#property version   "1.00"
#property strict
#property indicator_separate_window
#property indicator_buffers 2
#property indicator_plots   2
//--- plot Volume
#property indicator_label1  "Volume"
#property indicator_type1   DRAW_HISTOGRAM
#property indicator_color1  clrBlue
#property indicator_style1  STYLE_SOLID
#property indicator_width1  1
//--- plot Average
#property indicator_label2  "Average"
#property indicator_type2   DRAW_LINE
#property indicator_color2  clrRed
#property indicator_style2  STYLE_SOLID
#property indicator_width2  1
//--- input parameters
input int      MA_PERIOD=7;
//--- indicator buffers
double         VolumeBuffer[];
double         AverageBuffer[];
double tVolume;
int counted_bars,limit;
//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int OnInit()
  {
//--- indicator buffers mapping
   SetIndexBuffer(0,VolumeBuffer);
   SetIndexBuffer(1,AverageBuffer);
   
//---
   return(INIT_SUCCEEDED);
  }
//+------------------------------------------------------------------+
//| Custom indicator iteration function                              |
//+------------------------------------------------------------------+
int OnCalculate(const int rates_total,
                const int prev_calculated,
                const datetime &time[],
                const double &open[],
                const double &high[],
                const double &low[],
                const double &close[],
                const long &tick_volume[],
                const long &volume[],
                const int &spread[])
  {
//---
   counted_bars=IndicatorCounted();
   if(counted_bars==0){counted_bars=MA_PERIOD+1;}
   if(counted_bars>0){counted_bars--;}
   limit=Bars-counted_bars;
   for(int a=limit;a>=0;a--){
      VolumeBuffer[a]=iVolume(Symbol(),0,a);
      tVolume=0;
      for(int b=0;b<MA_PERIOD;b++){
         tVolume+=iVolume(Symbol(),0,a+b);
      }//loop b
      AverageBuffer[a]=tVolume/MA_PERIOD;
   }//loop a
//--- return value of prev_calculated for next call
   return(rates_total);
  }
//+------------------------------------------------------------------+