The trade cost of Forex Currency Part4

It is found that in USD account and GBP account, the calculated spread cost is exactly the same as the spread cost obtained from the real trading by comparison. Due to price fluctuations, the spread cost may differ slightly from the real spread cost.

3.  Test EA code

#include "SpreadCost.mqh"
#include <Trade\Trade.mqh>
//+------------------------------------------------------------------+
//| Global var                                                       |
//+------------------------------------------------------------------+
const double TestLots = 1.0;
string g_symbols[] = {"EURUSD","CADJPY","EURGBP","XAUEUR","EURHKD"};
int g_totalnum = 5;
int g_spread_output[5]; //output spread
double g_cost_output[5];//output cost
int g_spread_test[5];   //test spread by trade 
double g_cost_test[5];  //test cost by trade 
CTrade otrade;
CSpreadCost oSpreadCost(TestLots);
int OnInit()
{
   oSpreadCost.GetSymbolsSpreadCost(g_symbols,g_spread_output,g_cost_output);
   TradeSymbols();
   PrintInfo();
   return(INIT_SUCCEEDED);
}
//+------------------------------------------------------------------+
//| Expert deinitialization function                                 |
//+------------------------------------------------------------------+
void OnDeinit(const int reason)
  {
//---
  }
//+------------------------------------------------------------------+
//| Print spread and Trade Cost Info                                 |
//+------------------------------------------------------------------+
void PrintInfo()
{     
   string AccountCurrency = "USD";
   for(int i=0;i<g_totalnum;i++) 
   {
      AccountCurrency = AccountInfoString(ACCOUNT_CURRENCY);
      Print(i+1,". ",g_symbols[i]," OutputSpread is:",g_spread_output[i],", TestSpread is:",g_spread_test[i],
            ", OutputCost is:",DoubleToString(g_cost_output[i],2),"(",AccountCurrency,"), TestCost is:",
            DoubleToString(g_cost_test[i],2),"(",AccountCurrency,")!!"); 
   }
   
   return;
}
//+------------------------------------------------------------------+
//| Trade get test cost                                              |
//+------------------------------------------------------------------+
void TradeSymbols()
{
   MqlTick latest_price;
    
   for(int i = 0; i < g_totalnum; i++)
   {
      otrade.Buy(TestLots,g_symbols[i],latest_price.ask);
      
      PositionSelect(g_symbols[i]);
      g_spread_test[i] = (int)SymbolInfoInteger(g_symbols[i],SYMBOL_SPREAD);
      g_cost_test[i] = MathAbs(PositionGetDouble(POSITION_PROFIT));
      
      otrade.PositionClose(g_symbols[i],g_spread_output[i]*2);
   }
}