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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MQL5 Cookbook – Economic Calendar

MQL5 Cookbook – Economic Calendar

The article highlights the programming features of the Economic Calendar and considers creating a class for a simplified access to the calendar properties and receiving event values. Developing an indicator using CFTC non-commercial net positions serves as a practical example.
Creating Expert Advisors Using Expert Advisor Visual Wizard
Creating Expert Advisors Using Expert Advisor Visual Wizard

Creating Expert Advisors Using Expert Advisor Visual Wizard

Expert Advisor Visual Wizard for MetaTrader 5 provides a highly intuitive graphical environment with a comprehensive set of predefined trading blocks that let you design Expert Advisors in minutes. The click, drag and drop approach of Expert Advisor Visual Wizard allows you to create visual representations of forex trading strategies and signals as you would with pencil and paper. These trading diagrams are analyzed automatically by Molanis’ MQL5 code generator that transforms them into ready to use Expert Advisors. The interactive graphical environment simplifies the design process and eliminates the need to write MQL5 code.
Genetic Algorithms: Mathematics
Genetic Algorithms: Mathematics

Genetic Algorithms: Mathematics

Genetic (evolutionary) algorithms are used for optimization purposes. An example of such purpose can be neuronet learning, i.e., selection of such weight values that allow reaching the minimum error. At this, the genetic algorithm is based on the random search method.
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.
Quick Manual Trading Toolkit: Working with open positions and pending orders
Quick Manual Trading Toolkit: Working with open positions and pending orders

Quick Manual Trading Toolkit: Working with open positions and pending orders

In this article, we will expand the capabilities of the toolkit: we will add the ability to close trade positions upon specific conditions and will create tables for controlling market and pending orders, with the ability to edit these orders.
Analyzing trading results using HTML reports
Analyzing trading results using HTML reports

Analyzing trading results using HTML reports

The MetaTrader 5 platform features functionality for saving trading reports, as well as Expert Advisor testing and optimization reports. Trading and testing reports can be saved in two formats: XLSX and HTML, while the optimization report can be saved in XML. In this article we consider the HTML testing report, the XML optimization report and the HTML trading history report.
Learn how to design a trading system by ADX
Learn how to design a trading system by ADX

Learn how to design a trading system by ADX

In this article, we will continue our series about designing a trading system using the most popular indicators and we will talk about the average directional index (ADX) indicator. We will learn this indicator in detail to understand it well and we will learn how we to use it through a simple strategy. By learning something deeply we can get more insights and we can use it better.
Time Series Forecasting Using Exponential Smoothing (continued)
Time Series Forecasting Using Exponential Smoothing (continued)

Time Series Forecasting Using Exponential Smoothing (continued)

This article seeks to upgrade the indicator created earlier on and briefly deals with a method for estimating forecast confidence intervals using bootstrapping and quantiles. As a result, we will get the forecast indicator and scripts to be used for estimation of the forecast accuracy.
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.
How to Write a Good Description for a Market Product
How to Write a Good Description for a Market Product

How to Write a Good Description for a Market Product

MQL5 Market has many products for sale but some of their descriptions leave much to be desired. Many texts are obviously in need of improvement, as common traders are not able to comprehend them. This article will help you to put your product in a favorable light. Use our recommendations to write an eye-catching description that will easily show your customers what exactly you are selling.
Error Handling and Logging in MQL5
Error Handling and Logging in MQL5

Error Handling and Logging in MQL5

This article focuses on general issues linked to handling software errors. Furthermore, the logging term is brought up and the examples of logging implementation with MQL5 tools are shown.
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.
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Custom symbols: Practical basics

Custom symbols: Practical basics

The article is devoted to the programmatic generation of custom symbols which are used to demonstrate some popular methods for displaying quotes. It describes a suggested variant of minimally invasive adaptation of Expert Advisors for trading a real symbol from a derived custom symbol chart. MQL source codes are attached to this article.
MQL5 Cookbook: Indicator Subwindow Controls - Buttons
MQL5 Cookbook: Indicator Subwindow Controls - Buttons

MQL5 Cookbook: Indicator Subwindow Controls - Buttons

In this article, we will consider an example of developing a user interface with button controls. To convey the idea of interactivity to the user, buttons will change their colors when the cursor hovers over them. With the cursor being over a button, the button color will be slightly darkened, getting significantly darker when the button is clicked. Furthermore, we will add tooltips to each button, thus creating an intuitive interface.
Learn how to design a trading system by CCI
Learn how to design a trading system by CCI

Learn how to design a trading system by CCI

In this new article from our series for learning how to design trading systems, I will present the Commodities Channel Index (CCI), explain its specifics, and share with you how to create a trading system based on this indicator.
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.
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.
Library for easy and quick development of MetaTrader programs (part XIX): Class of library messages
Library for easy and quick development of MetaTrader programs (part XIX): Class of library messages

Library for easy and quick development of MetaTrader programs (part XIX): Class of library messages

In this article, we will consider the class of displaying text messages. Currently, we have a sufficient number of different text messages. It is time to re-arrange the methods of their storage, display and translation of Russian or English messages to other languages. Besides, it would be good to introduce convenient ways of adding new languages to the library and quickly switching between them.
MQL5 Cookbook: Implementing an Associative Array or a Dictionary for Quick Data Access
MQL5 Cookbook: Implementing an Associative Array or a Dictionary for Quick Data Access

MQL5 Cookbook: Implementing an Associative Array or a Dictionary for Quick Data Access

This article describes a special algorithm allowing to gain access to elements by their unique keys. Any base data type can be used as a key. For example it may be represented as a string or an integer variable. Such data container is commonly referred to as a dictionary or an associative array. It provides easier and more efficient way of problem solving.
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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Understanding order placement in MQL5

Understanding order placement in MQL5

When creating any trading system, there is a task we need to deal with effectively. This task is order placement or to let the created trading system deal with orders automatically because it is crucial in any trading system. So, you will find in this article most of the topics that you need to understand about this task to create your trading system in terms of order placement effectively.
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.
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.
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.
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.
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.
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.
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.
Reversing: Reducing maximum drawdown and testing other markets
Reversing: Reducing maximum drawdown and testing other markets

Reversing: Reducing maximum drawdown and testing other markets

In this article, we continue to dwell on reversing techniques. We will try to reduce the maximum balance drawdown till an acceptable level for the instruments considered earlier. We will see if the measures will reduce the profit. We will also check how the reversing method performs on other markets, including stock, commodity, index, ETF and agricultural markets. Attention, the article contains a lot of images!
Adaptive Trading Systems and Their Use in the MetaTrader 5 Client Terminal
Adaptive Trading Systems and Their Use in the MetaTrader 5 Client Terminal

Adaptive Trading Systems and Their Use in the MetaTrader 5 Client Terminal

This article suggests a variant of an adaptive system that consists of many strategies, each of which performs its own "virtual" trade operations. Real trading is performed in accordance with the signals of a most profitable strategy at the moment. Thanks to using of the object-oriented approach, classes for working with data and trade classes of the Standard library, the architecture of the system appeared to be simple and scalable; now you can easily create and analyze the adaptive systems that include hundreds of trade strategies.
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.
Testing (Optimization) Technique and Some Criteria for Selection of the Expert Advisor Parameters
Testing (Optimization) Technique and Some Criteria for Selection of the Expert Advisor Parameters

Testing (Optimization) Technique and Some Criteria for Selection of the Expert Advisor Parameters

There is no trouble finding the Holy Grail of testing, it is however much more difficult to get rid of it. This article addresses the selection of the Expert Advisor operating parameters with automated group processing of optimisation and testing results upon maximum utilisation of the Terminal performance capabilities and minimum end user load.
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.
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).
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OpenAI's ChatGPT features within the framework of MQL4 and MQL5 development

OpenAI's ChatGPT features within the framework of MQL4 and MQL5 development

In this article, we will fiddle around ChatGPT from OpenAI in order to understand its capabilities in terms of reducing the time and labor intensity of developing Expert Advisors, indicators and scripts. I will quickly navigate you through this technology and try to show you how to use it correctly for programming in MQL4 and MQL5.
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.
Rope Indicator by Erik Nayman
Rope Indicator by Erik Nayman

Rope Indicator by Erik Nayman

The article reveals how the "Rope" indicator is created based on "The Small Encyclopedia of Trader" by Erik L. Nayman. This indicator shows the direction of the trend using the calculated values of bulls and bears over a specified period of time. The article also contains principles of creating and calculating indicators along with the examples of codes. Other subjects covered include building an Expert Advisor based on the indicator, and the optimization of external parameters.
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Learn how to design a trading system by Ichimoku

Learn how to design a trading system by Ichimoku

Here is a new article in our series about how to design a trading system b the most popular indicators, we will talk about the Ichimoku indicator in detail and how to design a trading system by this indicator.