MQL4 and MQL5 Programming Articles

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Study the MQL5 language for programming trading strategies in numerous published articles mostly written by you - the community members. The articles are grouped into categories to help you quicker find answers to any questions related to programming: Integration, Tester, Trading Strategies, etc.

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Visualizing optimization results using a selected criterion
Visualizing optimization results using a selected criterion

Visualizing optimization results using a selected criterion

In the article, we continue to develop the MQL application for working with optimization results. This time, we will show how to form the table of the best results after optimizing the parameters by specifying another criterion via the graphical interface.
Timeseries in DoEasy library (part 40): Library-based indicators - updating data in real time
Timeseries in DoEasy library (part 40): Library-based indicators - updating data in real time

Timeseries in DoEasy library (part 40): Library-based indicators - updating data in real time

The article considers the development of a simple multi-period indicator based on the DoEasy library. Let's improve the timeseries classes to receive data from any timeframes to display it on the current chart period.
Applying OLAP in trading (part 1): Online analysis of multidimensional data
Applying OLAP in trading (part 1): Online analysis of multidimensional data

Applying OLAP in trading (part 1): Online analysis of multidimensional data

The article describes how to create a framework for the online analysis of multidimensional data (OLAP), as well as how to implement this in MQL and to apply such analysis in the MetaTrader environment using the example of trading account history processing.
Error 146 ("Trade context busy") and How to Deal with It
Error 146 ("Trade context busy") and How to Deal with It

Error 146 ("Trade context busy") and How to Deal with It

The article deals with conflict-free trading of several experts on one МТ 4 Client Terminal. It will be useful for those who have basic command of working with the terminal and programming in MQL 4.
Creating a new trading strategy using a technology of resolving entries into indicators
Creating a new trading strategy using a technology of resolving entries into indicators

Creating a new trading strategy using a technology of resolving entries into indicators

The article suggests a technology helping everyone to create custom trading strategies by assembling an individual indicator set, as well as to develop custom market entry signals.
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Learn how to design a trading system by Fractals

Learn how to design a trading system by Fractals

This article is a new one from our series about how to design a trading system based on the most popular technical indicators. We will learn a new indicator which Fractals indicator and we will learn how to design a trading system based on it to be executed in the MetaTrader 5 terminal.
Graphics in DoEasy library (Part 75): Methods of handling primitives and text in the basic graphical element
Graphics in DoEasy library (Part 75): Methods of handling primitives and text in the basic graphical element

Graphics in DoEasy library (Part 75): Methods of handling primitives and text in the basic graphical element

In this article, I will continue the development of the basic graphical element class of all library graphical objects powered by the CCanvas Standard Library class. I will create the methods for drawing graphical primitives and for displaying a text on a graphical element object.
How to Evaluate the Expert Testing Results
How to Evaluate the Expert Testing Results

How to Evaluate the Expert Testing Results

The article gives formulas and the calculation order for data shown in the Tester report.
Applying the probability theory to trading gaps
Applying the probability theory to trading gaps

Applying the probability theory to trading gaps

In this article, we will apply the probability theory and mathematical statistics methods to creating and testing trading strategies. We will also look for optimal trading risk using the differences between the price and the random walk. It is proved that if prices behave like a zero-drift random walk (with no directional trend), then profitable trading is impossible.
File Operations via WinAPI
File Operations via WinAPI

File Operations via WinAPI

Environment MQL4 is based on the conception of safe "sandbox": reading and saving files using the language are allowed in some predefined folders only. This protects the user of MetaTrader 4 from the potential danger of damaging important data on the HDD. However, it is sometimes necessary to leave that safe area. This article is devoted to the problem of how to do it easily and correctly.
3 Methods of Indicators Acceleration by the Example of the Linear Regression
3 Methods of Indicators Acceleration by the Example of the Linear Regression

3 Methods of Indicators Acceleration by the Example of the Linear Regression

The article deals with the methods of indicators computational algorithms optimization. Everyone will find a method that suits his/her needs best. Three methods are described here.One of them is quite simple, the next one requires solid knowledge of Math and the last one requires some wit. Indicators or MetaTrader5 terminal design features are used to realize most of the described methods. The methods are quite universal and can be used not only for acceleration of the linear regression calculation, but also for many other indicators.
Analyzing the Indicators Statistical Parameters
Analyzing the Indicators Statistical Parameters

Analyzing the Indicators Statistical Parameters

The technical analysis widely implements the indicators showing the basic quotes "more clearly" and allowing traders to perform analysis and forecast market prices movement. It's quite obvious that there is no sense in using the indicators, let alone applying them in creation of trading systems, unless we can solve the issues concerning initial quotes transformation and the obtained result credibility. In this article we show that there are serious reasons for such a conclusion.
FANN2MQL Neural Network Tutorial
FANN2MQL Neural Network Tutorial

FANN2MQL Neural Network Tutorial

This article has been made to show you how to use neural networks, via FANN2MQL, using an easy example: teaching a simple pattern to the neuralnetwork, and testing it to see if it can recognize patterns it has never seen.
Timeseries in DoEasy library (part 41): Sample multi-symbol multi-period indicator
Timeseries in DoEasy library (part 41): Sample multi-symbol multi-period indicator

Timeseries in DoEasy library (part 41): Sample multi-symbol multi-period indicator

In the article, we will consider a sample multi-symbol multi-period indicator using the timeseries classes of the DoEasy library displaying the chart of a selected currency pair on a selected timeframe as candles in a subwindow. I am going to modify the library classes a bit and create a separate file for storing enumerations for program inputs and selecting a compilation language.
DIY multi-threaded asynchronous MQL5 WebRequest
DIY multi-threaded asynchronous MQL5 WebRequest

DIY multi-threaded asynchronous MQL5 WebRequest

The article describes the library allowing you to increase the efficiency of working with HTTP requests in MQL5. Execution of WebRequest in non-blocking mode is implemented in additional threads that use auxiliary charts and Expert Advisors, exchanging custom events and reading shared resources. The source codes are applied as well.
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Learn how to design a trading system by Volumes

Learn how to design a trading system by Volumes

Here is a new article from our series about learning how to design a trading system based on the most popular technical indicators. The current article will be devoted to the Volumes indicator. Volume as a concept is one of the very important factors in financial markets trading and we have to pay attention to it. Through this article, we will learn how to design a simple trading system by Volumes indicator.
Self-adapting algorithm (Part III): Abandoning optimization
Self-adapting algorithm (Part III): Abandoning optimization

Self-adapting algorithm (Part III): Abandoning optimization

It is impossible to get a truly stable algorithm if we use optimization based on historical data to select parameters. A stable algorithm should be aware of what parameters are needed when working on any trading instrument at any time. It should not forecast or guess, it should know for sure.
Processing optimization results using the graphical interface
Processing optimization results using the graphical interface

Processing optimization results using the graphical interface

This is a continuation of the idea of processing and analysis of optimization results. This time, our purpose is to select the 100 best optimization results and display them in a GUI table. The user will be able to select a row in the optimization results table and receive a multi-symbol balance and drawdown graph on separate charts.
LifeHack for Trader: A comparative report of several tests
LifeHack for Trader: A comparative report of several tests

LifeHack for Trader: A comparative report of several tests

The article deals with the simultaneous launch of Expert Advisor testing on four different trading instruments. The final comparison of four testing reports is provided in a table similar to how goods are represented in online stores. An additional bonus is that distribution charts will be automatically created for each symbol.
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Mastering Market Dynamics: Creating a Support and Resistance Strategy Expert Advisor (EA)

Mastering Market Dynamics: Creating a Support and Resistance Strategy Expert Advisor (EA)

A comprehensive guide to developing an automated trading algorithm based on the Support and Resistance strategy. Detailed information on all aspects of creating an expert advisor in MQL5 and testing it in MetaTrader 5 – from analyzing price range behaviors to risk management.
Library for easy and quick development of MetaTrader programs (part XXIV): Base trading class - auto correction of invalid parameters
Library for easy and quick development of MetaTrader programs (part XXIV): Base trading class - auto correction of invalid parameters

Library for easy and quick development of MetaTrader programs (part XXIV): Base trading class - auto correction of invalid parameters

In this article, we will have a look at the handler of invalid trading order parameters and improve the trading event class. Now all trading events (both single ones and the ones occurred simultaneously within one tick) will be defined in programs correctly.
Market math: profit, loss and costs
Market math: profit, loss and costs

Market math: profit, loss and costs

In this article, I will show you how to calculate the total profit or loss of any trade, including commission and swap. I will provide the most accurate mathematical model and use it to write the code and compare it with the standard. Besides, I will also try to get on the inside of the main MQL5 function to calculate profit and get to the bottom of all the necessary values from the specification.
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Larry Williams Market Secrets (Part 2): Automating a Market Structure Trading System

Larry Williams Market Secrets (Part 2): Automating a Market Structure Trading System

Learn how to automate Larry Williams market structure concepts in MQL5 by building a complete Expert Advisor that reads swing points, generates trade signals, manages risk, and applies a dynamic trailing stop strategy.
Learn how to design a trading system by Momentum
Learn how to design a trading system by Momentum

Learn how to design a trading system by Momentum

In my previous article, I mentioned the importance of identifying the trend which is the direction of prices. In this article I will share one of the most important concepts and indicators which is the Momentum indicator. I will share how to design a trading system based on this Momentum indicator.
On Methods of Technical Analysis and Market Forecasting
On Methods of Technical Analysis and Market Forecasting

On Methods of Technical Analysis and Market Forecasting

The article demonstrates the capabilities and potential of a well-known mathematical method coupled with visual thinking and an "out of the box" market outlook. On the one hand, it serves to attract the attention of a wide audience as it can get the creative minds to reconsider the trading paradigm as such. And on the other, it can give rise to alternative developments and program code implementations regarding a wide range of tools for analysis and forecasting.
Graphical Interfaces I: Functions for the Form Buttons and Deleting Interface Elements (Chapter 4)
Graphical Interfaces I: Functions for the Form Buttons and Deleting Interface Elements (Chapter 4)

Graphical Interfaces I: Functions for the Form Buttons and Deleting Interface Elements (Chapter 4)

In this article, we are going to continue developing the CWindow class by adding methods, which will allow managing the form by clicking on its controls. We will enable the program to be closed by a form button as well as implement a minimizing and maximizing feature for the form.
Improved candlestick pattern recognition illustrated by the example of Doji
Improved candlestick pattern recognition illustrated by the example of Doji

Improved candlestick pattern recognition illustrated by the example of Doji

How to find more candlestick patterns than usual? Behind the simplicity of candlestick patterns, there is also a serious drawback, which can be eliminated by using the significantly increased capabilities of modern trading automation tools.
Grokking market "memory" through differentiation and entropy analysis
Grokking market "memory" through differentiation and entropy analysis

Grokking market "memory" through differentiation and entropy analysis

The scope of use of fractional differentiation is wide enough. For example, a differentiated series is usually input into machine learning algorithms. The problem is that it is necessary to display new data in accordance with the available history, which the machine learning model can recognize. In this article we will consider an original approach to time series differentiation. The article additionally contains an example of a self optimizing trading system based on a received differentiated series.
The Optimal Method for Calculation of Total Position Volume by Specified Magic Number
The Optimal Method for Calculation of Total Position Volume by Specified Magic Number

The Optimal Method for Calculation of Total Position Volume by Specified Magic Number

The problem of calculation of the total position volume of the specified symbol and magic number is considered in this article. The proposed method requests only the minimum necessary part of the history of deals, finds the closest time when the total position was equal to zero, and performs the calculations with the recent deals. Working with global variables of the client terminal is also considered.
Using MATLAB 2018 computational capabilities in MetaTrader 5
Using MATLAB 2018 computational capabilities in MetaTrader 5

Using MATLAB 2018 computational capabilities in MetaTrader 5

After the upgrade of the MATLAB package in 2015, it is necessary to consider a modern way of creating DLL libraries. The article uses a sample predictive indicator to illustrate the peculiarities of linking MetaTrader 5 and MATLAB using modern 64-bit versions of the platforms, which are utilized nowadays. With the entire sequence of connecting MATLAB considered, MQL5 developers will be able to create applications with advanced computational capabilities much faster, avoiding «pitfalls».
Secrets of the MetaTrader 4 Client Terminal: Indicators
Secrets of the MetaTrader 4 Client Terminal: Indicators

Secrets of the MetaTrader 4 Client Terminal: Indicators

Are you going to write your own indicator? Perhaps you will find that what you need among indicators already embedded in the client terminal. So why to reinvent the wheel? A summary table of integrated indicators' characteristics; special features and methods of attaching indicators to a chart; building of levels; displaying of indicators on different timeframes.
Interview with Achmad Hidayat (ATC 2012)
Interview with Achmad Hidayat (ATC 2012)

Interview with Achmad Hidayat (ATC 2012)

Throughout the entire duration of the Automated Trading Championship 2012, we will be providing live coverage of the events - hot reports and interviews every week. This report spotlights Achmad Hidayat (achidayat), the participant from Indonesia. On the first day of the Championship his Expert Advisor secured its position in the third ten, which is a good start. Achmad has sparked our interest with his active participation in the MQL5 Market. He has already published over 20 products thus far.
Universal Oscillator with a GUI
Universal Oscillator with a GUI

Universal Oscillator with a GUI

The article describes the process of creation of a universal indicator based on all oscillators available in the terminal, with its own graphical interface. The GUI allows users to quickly and easily change settings of each oscillator straight from the chart window (without having to open its properties), as well as to compare their values and to select an optimal option for a specific task.
OOP in MQL5 by Example: Processing Warning and Error Codes
OOP in MQL5 by Example: Processing Warning and Error Codes

OOP in MQL5 by Example: Processing Warning and Error Codes

The article describes an example of creating a class for working with the trade server return codes and all the errors that occur during the MQL-program run. Read the article, and you will learn how to work with classes and objects in MQL5. At the same time, this is a convenient tool for handling errors; and you can further change this tool according to your specific needs.
Reversing: Formalizing the entry point and developing a manual trading algorithm
Reversing: Formalizing the entry point and developing a manual trading algorithm

Reversing: Formalizing the entry point and developing a manual trading algorithm

This is the last article within the series devoted to the Reversing trading strategy. Here we will try to solve the problem, which caused the testing results instability in previous articles. We will also develop and test our own algorithm for manual trading in any market using the reversing strategy.
Studying candlestick analysis techniques (Part II): Auto search for new patterns
Studying candlestick analysis techniques (Part II): Auto search for new patterns

Studying candlestick analysis techniques (Part II): Auto search for new patterns

In the previous article, we analyzed 14 patterns selected from a large variety of existing candlestick formations. It is impossible to analyze all the patterns one by one, therefore another solution was found. The new system searches and tests new candlestick patterns based on known candlestick types.
Graphical Interfaces III: Groups of Simple and Multi-Functional Buttons (Chapter 2)
Graphical Interfaces III: Groups of Simple and Multi-Functional Buttons (Chapter 2)

Graphical Interfaces III: Groups of Simple and Multi-Functional Buttons (Chapter 2)

The first chapter of the series was about simple and multi-functional buttons. The second article will be dedicated to groups of interconnected buttons that will allow the creation of elements in an application when a user can select one of the option out of a set (group).
Comfortable Scalping
Comfortable Scalping

Comfortable Scalping

The article describes the method of creating a tool for comfortable scalping. However, such an approach to trade opening can be applied in any trading.
Kernel Density Estimation of the Unknown Probability Density Function
Kernel Density Estimation of the Unknown Probability Density Function

Kernel Density Estimation of the Unknown Probability Density Function

The article deals with the creation of a program allowing to estimate the kernel density of the unknown probability density function. Kernel Density Estimation method has been chosen for executing the task. The article contains source codes of the method software implementation, examples of its use and illustrations.
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Dealing with Time (Part 2): The Functions

Dealing with Time (Part 2): The Functions

Determing the broker offset and GMT automatically. Instead of asking the support of your broker, from whom you will probably receive an insufficient answer (who would be willing to explain a missing hour), we simply look ourselves how they time their prices in the weeks of the time changes — but not cumbersome by hand, we let a program do it — why do we have a PC after all.