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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An Example of a Trading System Based on a Heiken-Ashi Indicator
An Example of a Trading System Based on a Heiken-Ashi Indicator

An Example of a Trading System Based on a Heiken-Ashi Indicator

In this article we look into the question of using a Heiken-Ashi indicator in trading. Based on this indicator, a simple trading system is considered and an MQL5 Expert Advisor is written. Trading operations are implemented on the bases of classes of the Standard class library. The testing results of the reviewed trading strategy, are based on the history, and obtained using the built-in MetaTrader 5 strategy tester, are provided in the article.
Using WinInet.dll for Data Exchange between Terminals via the Internet
Using WinInet.dll for Data Exchange between Terminals via the Internet

Using WinInet.dll for Data Exchange between Terminals via the Internet

This article describes the principles of working with the Internet via the use of HTTP requests, and data exchange between terminals, using an intermediate server. An MqlNet library class is presented for working with Internet resources in the MQL5 environment. Monitoring prices from different brokers, exchanging messages with other traders without exiting the terminal, searching for information on the Internet – these are just some examples, reviewed in this article.
Creating a Multi-Currency Indicator, Using a Number of Intermediate Indicator Buffers
Creating a Multi-Currency Indicator, Using a Number of Intermediate Indicator Buffers

Creating a Multi-Currency Indicator, Using a Number of Intermediate Indicator Buffers

There has been a recent rise of interest in the cluster analyses of the FOREX market. MQL5 opens up new possibilities of researching the trends of the movement of currency pairs. A key feature of MQL5, differentiating it from MQL4, is the possibility of using an unlimited amount of indicator buffers. This article describes an example of the creation of a multi-currency indicator.
Step-By-Step Guide to writing an Expert Advisor in MQL5 for Beginners
Step-By-Step Guide to writing an Expert Advisor in MQL5 for Beginners

Step-By-Step Guide to writing an Expert Advisor in MQL5 for Beginners

The Expert Advisors programming in MQL5 is simple, and you can learn it easy. In this step by step guide, you will see the basic steps required in writing a simple Expert Advisor based on a developed trading strategy. The structure of an Expert Advisor, the use of built-in technical indicators and trading functions, the details of the Debug mode and use of the Strategy Tester are presented.
Connection of Expert Advisor with ICQ in MQL5
Connection of Expert Advisor with ICQ in MQL5

Connection of Expert Advisor with ICQ in MQL5

This article describes the method of information exchange between the Expert Advisor and ICQ users, several examples are presented. The provided material will be interesting for those, who wish to receive trading information remotely from a client terminal, through an ICQ client in their mobile phone or PDA.
New Opportunities with MetaTrader 5
New Opportunities with MetaTrader 5

New Opportunities with MetaTrader 5

MetaTrader 4 gained its popularity with traders from all over the world, and it seemed like nothing more could be wished for. With its high processing speed, stability, wide array of possibilities for writing indicators, Expert Advisors, and informatory-trading systems, and the ability to chose from over a hundred different brokers, - the terminal greatly distinguished itself from the rest. But time doesn’t stand still, and we find ourselves facing a choice of MetaTrade 4 or MetaTrade 5. In this article, we will describe the main differences of the 5th generation terminal from our current favor.
The Algorithm of Ticks' Generation within the Strategy Tester of the MetaTrader 5 Terminal
The Algorithm of Ticks' Generation within the Strategy Tester of the MetaTrader 5 Terminal

The Algorithm of Ticks' Generation within the Strategy Tester of the MetaTrader 5 Terminal

MetaTrader 5 allows us to simulate automatic trading, within an embedded strategy tester, by using Expert Advisors and the MQL5 language. This type of simulation is called testing of Expert Advisors, and can be implemented using multithreaded optimization, as well as simultaneously on a number of instruments. In order to provide a thorough testing, a generation of ticks based on the available minute history, needs to be performed. This article provides a detailed description of the algorithm, by which the ticks are generated for the historical testing in the MetaTrader 5 client terminal.
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.
MQL for "Dummies": How to Design and Construct Object Classes
MQL for "Dummies": How to Design and Construct Object Classes

MQL for "Dummies": How to Design and Construct Object Classes

By creating a sample program of visual design, we demonstrate how to design and construct classes in MQL5. The article is written for beginner programmers, who are working on MT5 applications. We propose a simple and easy grasping technology for creating classes, without the need to deeply immerse into the theory of object-oriented programming.
Creating Active Control Panels in MQL5 for Trading
Creating Active Control Panels in MQL5 for Trading

Creating Active Control Panels in MQL5 for Trading

The article covers the problem of development of active control panels in MQL5. Interface elements are managed by the event handling mechanism. Besides, the option of a flexible setup of control elements properties is available. The active control panel allows working with positions, as well setting, modifying and deleting market and pending orders.
Practical Application Of Databases For Markets Analysis
Practical Application Of Databases For Markets Analysis

Practical Application Of Databases For Markets Analysis

Working with data has become the main task for modern software - both for standalone and network applications. To solve this problem a specialized software were created. These are Database Management Systems (DBMS), that can structure, systematize and organize data for their computer storage and processing. As for trading, the most of analysts don't use databases in their work. But there are tasks, where such a solution would have to be handy. This article provides an example of indicators, that can save and load data from databases both with client-server and file-server architectures.
Migrating from MQL4 to MQL5
Migrating from MQL4 to MQL5

Migrating from MQL4 to MQL5

This article is a quick guide to MQL4 language functions, it will help you to migrate your programs from MQL4 to MQL5. For each MQL4 function (except trading functions) the description and MQL5 implementation are presented, it allows you to reduce the conversion time significantly. For convenience, the MQL4 functions are divided into groups, similar to MQL4 Reference.
A Virtual Order Manager to track orders within the position-centric MetaTrader 5 environment
A Virtual Order Manager to track orders within the position-centric MetaTrader 5 environment

A Virtual Order Manager to track orders within the position-centric MetaTrader 5 environment

This class library can be added to an MetaTrader 5 Expert Advisor to enable it to be written with an order-centric approach broadly similar to MetaTrader 4, in comparison to the position-based approach of MetaTrader 5. It does this by keeping track of virtual orders at the MetaTrader 5 client terminal, while maintaining a protective broker stop for each position for disaster protection.
Creating an Indicator with Graphical Control Options
Creating an Indicator with Graphical Control Options

Creating an Indicator with Graphical Control Options

Those who are familiar with market sentiments, know the MACD indicator (its full name is Moving Average Convergence/Divergence) - the powerful tool for analyzing the price movement, used by traders from the very first moments of appearance of the computer analysis methods. In this article we'll consider possible modifications of MACD and implement them in one indicator with the possibility to graphically switch between the modifications.
MetaTrader 5: Publishing trading forecasts and live trading statements via e-mail on blogs, social networks and dedicated websites
MetaTrader 5: Publishing trading forecasts and live trading statements via e-mail on blogs, social networks and dedicated websites

MetaTrader 5: Publishing trading forecasts and live trading statements via e-mail on blogs, social networks and dedicated websites

This article aims to present ready-made solutions for publishing forecasts using MetaTrader 5. It covers a range of ideas: from using dedicated websites for publishing MetaTrader statements, through setting up one's own website with virtually no web programming experience needed and finally integration with a social network microblogging service that allows many readers to join and follow the forecasts. All solutions presented here are 100% free and possible to setup by anyone with a basic knowledge of e-mail and ftp services. There are no obstacles to use the same techniques for professional hosting and commercial trading forecast services.
Creating a "Snake" Game in MQL5
Creating a "Snake" Game in MQL5

Creating a "Snake" Game in MQL5

This article describes an example of "Snake" game programming. In MQL5, the game programming became possible primarily due to event handling features. The object-oriented programming greatly simplifies this process. In this article, you will learn the event processing features, the examples of use of the Standard MQL5 Library classes and details of periodic function calls.
Creating Tick Indicators in MQL5
Creating Tick Indicators in MQL5

Creating Tick Indicators in MQL5

In this article, we will consider the creation of two indicators: the tick indicator, which plots the tick chart of the price and tick candle indicator, which plot candles with the specified number of ticks. Each of the indicators writes the incoming prices into a file, and uses the saved data after the restart of the indicator (these data also can be used by the other programs)
Using the Object Pointers in MQL5
Using the Object Pointers in MQL5

Using the Object Pointers in MQL5

By default, all objects in MQL5 are passed by reference, but there is a possibility to use the object pointers. However it's necessary to perform the pointer checking, because the object may be not initialized. In this case, the MQL5 program will be terminated with critical error and unloaded. The objects, created automatically, doesn't cause such an error, so in this sence, they are quite safe. In this article, we will try to understand the difference between the object reference and object pointer, and consider how to write secure code, that uses the pointers.
MQL5: Analysis and Processing of Commodity Futures Trading Commission (CFTC) Reports in MetaTrader 5
MQL5: Analysis and Processing of Commodity Futures Trading Commission (CFTC) Reports in MetaTrader 5

MQL5: Analysis and Processing of Commodity Futures Trading Commission (CFTC) Reports in MetaTrader 5

In this article, we will develop a tool for CFTC report analysis. We will solve the following problem: to develop an indicator, that allows using the CFTC report data directly from the data files provided by Commission without an intermediate processing and conversion. Further, it can be used for the different purposes: to plot the data as an indicator, to proceed with the data in the other indicators, in the scripts for the automated analysis, in the Expert Advisors for the use in the trading strategies.
Introduction to MQL5: How to write simple Expert Advisor and Custom Indicator
Introduction to MQL5: How to write simple Expert Advisor and Custom Indicator

Introduction to MQL5: How to write simple Expert Advisor and Custom Indicator

MetaQuotes Programming Language 5 (MQL5), included in MetaTrader 5 Client Terminal, has many new possibilities and higher performance, compared to MQL4. This article will help you to get acquainted with this new programming language. The simple examples of how to write an Expert Advisor and Custom Indicator are presented in this article. We will also consider some details of MQL5 language, that are necessary to understand these examples.
Drawing Indicator's Emissions in MQL5
Drawing Indicator's Emissions in MQL5

Drawing Indicator's Emissions in MQL5

In this article, we will consider the emission of indicators - a new approach to the market research. The calculation of emission is based on the intersection of different indicators: more and more points with different colors and shapes appear after each tick. They form numerous clusters like nebulae, clouds, tracks, lines, arcs, etc. These shapes help to detect the invisible springs and forces that affect the movement of market prices.
The Drawing Styles in MQL5
The Drawing Styles in MQL5

The Drawing Styles in MQL5

There are 6 drawing styles in MQL4 and 18 drawing styles in MQL5. Therefore, it may be worth writing an article to introduce MQL5's drawing styles. In this article, we will consider the details of drawing styles in MQL5. In addition, we will create an indicator to demonstrate how to use these drawing styles, and refine the plotting.
Practical Implementation of Digital Filters in MQL5 for Beginners
Practical Implementation of Digital Filters in MQL5 for Beginners

Practical Implementation of Digital Filters in MQL5 for Beginners

The idea of digital signal filtering has been widely discussed on forum topics about building trading systems. And it would be imprudent not to create a standard code of digital filters in MQL5. In this article the author describes the transformation of simple SMA indicator's code from his article "Custom Indicators in MQL5 for Newbies" into code of more complicated and universal digital filter. This article is a logical sequel to the previous article. It also tells how to replace text in code and how to correct programming errors.
MQL5 for Newbies: Guide to Using Technical Indicators in Expert Advisors
MQL5 for Newbies: Guide to Using Technical Indicators in Expert Advisors

MQL5 for Newbies: Guide to Using Technical Indicators in Expert Advisors

In order to obtain values of a built-in or custom indicator in an Expert Advisor, first its handle should be created using the corresponding function. Examples in the article show how to use this or that technical indicator while creating your own programs. The article describes indicators that are built n the MQL5 language. It is intended for those who don't have much experience in the development of trading strategies and offers simple and clear ways of working with indicators using the offered library of functions.
Event handling in MQL5: Changing MA period on-the-fly
Event handling in MQL5: Changing MA period on-the-fly

Event handling in MQL5: Changing MA period on-the-fly

Suppose that simple MA (Moving Average) indicator with period 13 is applied to a chart. And we want to change the period to 20, but we do not want to go to indicator properties dialog box and edit the number 13 to 20: simply tired of these tedious actions with mouse and keyboard. And especially we don't want to open indicator code and modify it. We want to do all this with a single press of a button - "up arrows" next to the numeric keypad. In this article I'll describe how to do it.
How to call indicators in MQL5
How to call indicators in MQL5

How to call indicators in MQL5

With new version of MQL programming language available not only the approach of dealing with indicators have changed, but there are also new ways of how to create indicators. Furthermore, you have additional flexibility working with indicator's buffers - now you can specify the desired direction of indexing and get exactly as many indicator's values as you want. This article explains the basic methods of calling indicators and retrieving data from the indicator's buffers.
Custom Indicators in MQL5 for Newbies
Custom Indicators in MQL5 for Newbies

Custom Indicators in MQL5 for Newbies

Any new subject seems complicated and hard-to-learn for a newbie. Subjects that we know seem very simple and clear to us. But we simply do not remember, that everyone has to study something from scratch, and even our native language. The same is with the MQL5 programming language that offers wide possibilities of developing one's own trading strategies - you can start learning it from basic notions and simplest examples. Interaction of a technical indicator with the MetaTrader 5 client terminal is consider in this article on the example of the simple custom indicator SMA.
The Order of Object Creation and Destruction in MQL5
The Order of Object Creation and Destruction in MQL5

The Order of Object Creation and Destruction in MQL5

Every object, whether it is a custom object, a dynamic array or an array of objects, is created and deleted in MQL5-program in its particular way. Often, some objects are part of other objects, and the order of object deleting at deinitialization becomes especially important. This article provides some examples that cover the mechanisms of working with objects.
MQL5.community - User Memo
MQL5.community - User Memo

MQL5.community - User Memo

You have just registered and most likely you have questions such as, "How do I insert a picture to my a message?" "How do I format my MQL5 source code?" "Where are my personal messages kept?" You may have many other questions. In this article, we have prepared some hands-on tips that will help you get accustomed in MQL5.community and take full advantage of its available features.
How to Export Quotes from МetaTrader 5 to .NET Applications Using WCF Services
How to Export Quotes from МetaTrader 5 to .NET Applications Using WCF Services

How to Export Quotes from МetaTrader 5 to .NET Applications Using WCF Services

Want to organize export of quotes from MetaTrader 5 to your own application? The MQL5-DLL junction allows to create such solutions! This article will show you one of the ways to export quotes from MetaTrader 5 to applications written in .NET. For me it was more interesting, rational and easy to implement export of quotes using this very platform. Unfortunately, version 5 still does not support .NET, so like in old days we will use win32 dll with .NET support as an interlayer.
Applying One Indicator to Another
Applying One Indicator to Another

Applying One Indicator to Another

When writing an indicator that uses the short form of the OnCalculate() function call, you might miss the fact that an indicator can be calculated not only by price data, but also by data of some other indicator (no matter whether it is a built-in or custom one). Do you want to improve an indicator for its correct application to the other indicator's data? In this article we'll review all the steps required for such modification.
The Price Histogram (Market Profile) and its implementation in MQL5
The Price Histogram (Market Profile) and its implementation in MQL5

The Price Histogram (Market Profile) and its implementation in MQL5

The Market Profile was developed by trully brilliant thinker Peter Steidlmayer. He suggested to use the alternative representation of information about "horizontal" and "vertical" market movements that leads to completely different set of models. He assumed that there is an underlying pulse of the market or a fundamental pattern called the cycle of equilibrium and disequilibrium. In this article I will consider Price Histogram — a simplified model of Market Profile, and will describe its implementation in MQL5.
How to Exchange Data: A DLL for MQL5 in 10 Minutes
How to Exchange Data: A DLL for MQL5 in 10 Minutes

How to Exchange Data: A DLL for MQL5 in 10 Minutes

Now not so many developers remember how to write a simple DLL, and what are special features of different system binding. Using several examples, I will try to show the entire process of the simple DLL's creation in 10 minutes, as well as to discuss some technical details of our binding implementation. I will show the step-by-step process of DLL creation in Visual Studio with examples of exchanging different types of variables (numbers, arrays, strings, etc.). Besides I will explain how to protect your client terminal from crashes in custom DLLs.
Data Exchange between Indicators: It's Easy
Data Exchange between Indicators: It's Easy

Data Exchange between Indicators: It's Easy

We want to create such an environment, which would provide access to data of indicators attached to a chart, and would have the following properties: absence of data copying; minimal modification of the code of available methods, if we need to use them; MQL code is preferable (of course, we have to use DLL, but we will use just a dozen of strings of C++ code). The article describes an easy method to develop a program environment for the MetaTrader terminal, that would provide means for accessing indicator buffers from other MQL programs.
MQL5: Create Your Own Indicator
MQL5: Create Your Own Indicator

MQL5: Create Your Own Indicator

What is an indicator? It is a set of calculated values that we want to be displayed on the screen in a convenient way. Sets of values are represented in programs as arrays. Thus, creation of an indicator means writing an algorithm that handles some arrays (price arrays) and records results of handling to other arrays (indicator values). By describing creation of True Strength Index, the author shows how to write indicators in MQL5.
Here Comes the New MetaTrader 5 and MQL5
Here Comes the New MetaTrader 5 and MQL5

Here Comes the New MetaTrader 5 and MQL5

This is just a brief review of MetaTrader 5. I can't describe all the system's new features for such a short time period - the testing started on 2009.09.09. This is a symbolical date, and I am sure it will be a lucky number. A few days have passed since I got the beta version of the MetaTrader 5 terminal and MQL5. I haven't managed to try all its features, but I am already impressed.
Step on New Rails: Custom Indicators in MQL5
Step on New Rails: Custom Indicators in MQL5

Step on New Rails: Custom Indicators in MQL5

I will not list all of the new possibilities and features of the new terminal and language. They are numerous, and some novelties are worth the discussion in a separate article. Also there is no code here, written with object-oriented programming, it is a too serous topic to be simply mentioned in a context as additional advantages for developers. In this article we will consider the indicators, their structure, drawing, types and their programming details, as compared to MQL4. I hope that this article will be useful both for beginners and experienced developers, maybe some of them will find something new.
Auto-Generated Documentation for MQL5 Code
Auto-Generated Documentation for MQL5 Code

Auto-Generated Documentation for MQL5 Code

Most Java coders will be familiar with the auto-generated documentation that can be created with JavaDocs. The idea is to add comments into the code in a semi-structured way that can then be extracted into an easy to navigate help file. The C++ world also has a number of documentation auto-generators, with Microsoft's SandCastle and Doxygen being two leaders. The article describes the use of Doxygen to create HTML help file from structured comments in MQL5 code. The experiment worked very well and I believe the help documentation that Doxygen produces from MQL5 code will add a great deal of value.