Hello world to quantitative trading with MT5

Hello world to MQL5

//+------------------------------------------------------------------+
//|                                                   HelloWorld.mq5 |
//|                                  Copyright 2022, MetaQuotes Ltd. |
//|                                             https://www.mql5.com |
//+------------------------------------------------------------------+
#property copyright "Copyright 2022, MetaQuotes Ltd."
#property link      "https://www.mql5.com"
#property version   "1.00"

#include <Trade\Trade.mqh>
int MaSlow, MaFast;
CTrade Trade;
input int slowPeriod = 10, 
          fastPeriod = 5;

//+------------------------------------------------------------------+
//| Expert initialization function                                   |
//+------------------------------------------------------------------+
int OnInit() {
   MaSlow = iMA(_Symbol, _Period, slowPeriod, 0, MODE_SMA, PRICE_CLOSE);
   MaFast = iMA(_Symbol, _Period, fastPeriod, 0, MODE_SMA, PRICE_CLOSE);
   if (MaSlow == INVALID_HANDLE || MaFast == INVALID_HANDLE)
      return INIT_FAILED;
   
   // Invokes `OnTimer` on every bar close
   Sleep((TimeCurrent() % GetCountDown()) * 1000);
   EventSetTimer(GetCountDown()); 
   return INIT_SUCCEEDED;
}

//+------------------------------------------------------------------+
//| Maps the PERIOD enumeration to time intervals in second.         |
//+------------------------------------------------------------------+
int GetCountDown() {
   if(_Period == PERIOD_D1) return 86400;
   if(_Period == PERIOD_H1) return 3600;
   if(_Period == PERIOD_M30) return 1800;
   if(_Period == PERIOD_M20) return 1200;
   if(_Period == PERIOD_M15) return 900;
   if(_Period == PERIOD_M12) return 720;
   if(_Period == PERIOD_M10) return 600;
   if(_Period == PERIOD_M5) return 300;
   if(_Period == PERIOD_M3) return 180;
   if(_Period == PERIOD_M1) return 60;
   return 0;
}


//+------------------------------------------------------------------+
//| Expert deinitialization function                                 |
//+------------------------------------------------------------------+
void OnDeinit(const int reason) { }

//+------------------------------------------------------------------+
//| Expert timer function                                            |
//+------------------------------------------------------------------+
void OnTimer() {
   double slowValue[1], fastValue[1];
   if (CopyBuffer(MaSlow, 0, 0, 1, slowValue) != 1) return;
   if (CopyBuffer(MaFast, 0, 0, 1, fastValue) != 1) return;
   double latestPrice = iClose(_Symbol, _Period, 0);
   
   PositionSelect(_Symbol);
   double currentPosition = PositionGetDouble(POSITION_VOLUME), 
          targetPosition = 0;
   int direction = PositionGetInteger(POSITION_TYPE);
   currentPosition *= direction == POSITION_TYPE_SELL ? -1 : 1;
   
   if (slowValue[0] < fastValue[0]) {
      targetPosition = -1;
   }
   if (slowValue[0] > fastValue[0]) {
      targetPosition = 1;
   }
   printf("%lf %lf", targetPosition, currentPosition);
   
   // MQL omits precision errors for equality of floating point numbers
   if (currentPosition != targetPosition) {
      Trade.PositionClose(_Symbol);
      
      if (targetPosition > 0) {
         Trade.Buy(1, _Symbol, 0.0
            // TODO: Uncomment this line to enable stoploss at distance of 0.1
            /*, latestPrice - 0.1 */
         );
      }
      if (targetPosition < 0) {
         Trade.Sell(1, _Symbol, 0.0
            // TODO: Uncomment this line to enable stoploss at distance of 0.1
            /* , latestPrice + 0.1 */
         );
      }
   }
}
//+------------------------------------------------------------------+