What is MQL programming?

 

What is MQL Programming?

MQL, or MetaQuotes Language, is a specialized programming language used for developing trading strategies, scripts, and custom indicators for the MetaTrader trading platform. There are two primary versions of MQL:

1. MQL4: Used for MetaTrader 4 (MT4).
2. MQL5: Used for MetaTrader 5 (MT5).

Both languages share similarities but also have significant differences, particularly in their approach to order handling and execution.

Key Features of MQL

1. Algorithmic Trading:

   • Develop automated trading systems (Expert Advisors or EAs) that can open, manage, and close trades without human intervention.

2. Custom Indicators:

   • Create technical indicators that are not available in the default set provided by MetaTrader.

3. Scripts:

   • Write scripts for single-run tasks such as closing all orders, calculating lot sizes, or performing other one-off operations.

4. Libraries:

   • Develop reusable code libraries that can be shared across multiple EAs, indicators, or scripts.

5. Integration:

   • Seamlessly integrates with MetaTrader 4 and MetaTrader 5, making it ideal for Forex and CFD trading.

Basic Structure of MQL Programs

An MQL program typically consists of the following sections:

1. Declarations: Variables, constants, and input parameters are declared at the beginning.
2. Initialization: Code that runs once when the program starts (OnInit()).
3. Deinitialization: Code that runs once when the program stops (OnDeinit()).
4. Main Execution: Code that runs repeatedly based on incoming market ticks (OnTick()) or other events (OnTrade(), OnTimer(), etc.).

Example of an MQL4 Expert Advisor

Here's a simple example of an MQL4 Expert Advisor (EA) that opens a buy trade when the price crosses above a simple moving average (SMA):

//+------------------------------------------------------------------+
//|                                            SimpleMovingAverageEA |
//|                        Copyright 2024, MetaQuotes Software Corp. |
//|                                       http://www.metaquotes.net/ |
//+------------------------------------------------------------------+
#property strict

// Input parameters
input int MA_Period = 14;
input double LotSize = 0.1;
input double StopLoss = 50;  // Stop loss in pips
input double TakeProfit = 100;  // Take profit in pips

// Global variables
double MovingAverage;

//+------------------------------------------------------------------+
//| Expert initialization function                                   |
//+------------------------------------------------------------------+
int OnInit()
  {
   Print("Simple Moving Average EA initialized");
   return INIT_SUCCEEDED;
  }
//+------------------------------------------------------------------+
//| Expert deinitialization function                                 |
//+------------------------------------------------------------------+
void OnDeinit(const int reason)
  {
   Print("Simple Moving Average EA deinitialized");
  }
//+------------------------------------------------------------------+
//| Expert tick function                                             |
//+------------------------------------------------------------------+
void OnTick()
  {
   // Calculate the Simple Moving Average (SMA)
   MovingAverage = iMA(Symbol(), 0, MA_Period, 0, MODE_SMA, PRICE_CLOSE, 0);

   // Check if the price has crossed above the SMA
   if (Close[1] < MovingAverage && Close[0] > MovingAverage)
     {
      // Calculate stop loss and take profit prices
      double sl = Bid - StopLoss * Point;
      double tp = Bid + TakeProfit * Point;

      // Open a buy trade
      int ticket = OrderSend(Symbol(), OP_BUY, LotSize, Ask, 3, sl, tp, "Simple MA Buy", 0, 0, Green);
      if (ticket < 0)
        {
         Print("Error opening order: ", GetLastError());
        }
      else
        {
         Print("Order opened successfully: ", ticket);
        }
     }
  }
//+------------------------------------------------------------------+

Key Functions in MQL

1. OrderSend(): Places an order to buy or sell.
2. OrderClose(): Closes an existing order.
3. iMA(): Calculates the moving average.
4. iRSI(), iMACD(), iCCI(): Functions to calculate various technical indicators.
5. Print(): Outputs messages to the log, useful for debugging.

Advantages of MQL

• Integrated Environment: MQL is tightly integrated with MetaTrader, providing easy access to trading functions and market data.
• Community and Resources: A large community of traders and developers sharing strategies, indicators, and EAs.
• Backtesting: Robust backtesting capabilities to evaluate the performance of trading strategies using historical data.

Conclusion

MQL programming is essential for traders using MetaTrader 4 and 5 who want to automate their trading strategies, develop custom indicators, and perform advanced market analysis. The language's integration with MetaTrader and its specific functions for trading operations make it a powerful tool for algorithmic trading in Forex and CFD markets.