//+------------------------------------------------------------------+
//|                                                   SymbolLots.mq4 |
//|                                              Copyright 2020, AM2 |
//|                                      http://www.forexsystems.biz |
//+------------------------------------------------------------------+
#property copyright "Copyright 2020, AM2"
#property link      "http://www.forexsystems.biz"
#property version   "1.00"
#property strict
#property indicator_chart_window

string symbols[11];
double vol[11];
//+------------------------------------------------------------------+
//| Custom indicator initialization function                         |
//+------------------------------------------------------------------+
int OnInit()
  {
//--- indicator buffers mapping
   Comment("");
//---
   return(INIT_SUCCEEDED);
  }
//+------------------------------------------------------------------+
//|                                                                  |
//+------------------------------------------------------------------+
bool Symb(string s="")
  {
   for(int i=0; i<11; i++)
     {
      if(symbols[i]==s)
         return(false);
     }
   return(true);
  }
//+------------------------------------------------------------------+
//|                                                                  |
//+------------------------------------------------------------------+
double Vol(string symb="")
  {
   double v=0;

   for(int i=0; i<OrdersTotal(); i++)
     {
      if(OrderSelect(i,SELECT_BY_POS,MODE_TRADES))
        {
         if(OrderSymbol()==symb)
           {
            v+=OrderLots();
           }
        }
     }
   return(v);
  }
//+------------------------------------------------------------------+
//| 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[])
  {
//---
   string s="";

   for(int i=0,k=0; i<OrdersTotal(); i++)
     {
      if(OrderSelect(i,SELECT_BY_POS,MODE_TRADES))
        {
         if(Symb(OrderSymbol()))
           {
            symbols[k]=OrderSymbol();
            k++;
           }
        }
     }

   for(int i=0; i<ArraySize(symbols); i++)
     {
      s+="\n"+symbols[i];
      vol[i]=Vol(symbols[i]);
      ArraySort(vol,WHOLE_ARRAY,0,MODE_DESCEND);
     }

   Comment(s+(string)vol[0]);

//--- return value of prev_calculated for next call
   return(rates_total);
  }
//+------------------------------------------------------------------+

//+------------------------------------------------------------------+