MQL4 and MQL5 Programming Articles

Another quarter of the year has passed and we have decided to sum up its results for MetaTrader AppStore - the largest store of trading robots and technical indicators for MetaTrader platforms. More than 500 developers have placed over 1 200 products in the Market by the end of the reported quarter.

In the article "Dr. Tradelove..." we created an Expert Advisor, which independently optimizes parameters of a pre-selected trading system. Moreover, we decided to create an Expert Advisor that can not only optimize parameters of one trading system underlying the EA, but also select the best one of several trading systems. Let's see what can come of it...

Since I published the article "Alert and Comment for External Indicators", I have been receiving requests and questions regarding the possibility of developing an external informer operating based on indicator lines. Having analyzed the questions, I have decided to continue with the subject. Getting data stored in indicator buffers turned out to be another area of interest to users.

In this article, I will complete working with chart object classes and their collection. I will also implement auto tracking of changes in chart properties and their windows, as well as saving new parameters to the object properties. Such a revision allows the future implementation of an event functionality for the entire chart collection.

It is time to start the integration of the already created objects into the previously created library objects. This will ultimately endow each library object with its own graphical object allowing users to interact with the program.

The article regards spindle chart plotting and its usage in trading strategies and experts. First let's discuss the chart's appearance, plotting and connection with japanese candlestick chart. Next we analyze the indicator's implementation in the source code in the MQL5 language. Let's test the expert based on indicator and formulate the trading strategy.

A rather universal approach to writing indicators of the ZigZag type is proposed. The method includes a significant part of ZigZags already described and allows you to create new ones relatively easily.

We usually analyze the market using candlesticks or bars that slice the price series into regular intervals. Doesn't such discretization method distort the real structure of market movements? Discretization of an audio signal at regular intervals is an acceptable solution because an audio signal is a function that changes over time. The signal itself is an amplitude which depends on time. This signal property is fundamental.

This article considers creation of documentation for MQL5 code starting with the automated markup of required tags. It also provides the description of how to use the Doxygen software, how to properly configure it and how to receive results in different formats, including html, HtmlHelp and PDF.

The entire complex of problems of creating a structure of an executed code and its tracing can be solved without serious difficulties. This possibility has appeared in MetaTrader 5 due to the new feature of the MQL5 language - automatic creation of variables of complex type of data (structures and classes) and their elimination when going out of local scope. The article contains the description of the methodology and the ready-made tool.

In this article, we will learn how we can build an Aroon trading system after learning the basics of the indicators and the needed steps to build a trading system based on the Aroon indicator. After building this trading system, we will test it to see if it can be profitable or needs more optimization.

In this article, I will start the improvement of the indicator buffer objects and collection class for working in multi-period and multi-symbol modes. I am going to consider the operation of buffer objects for receiving and displaying data from any timeframe on the current symbol chart.

The most of traders use special programs to protect their PCs. Unfortunately, these programs don't only protect computers against intrusions, viruses and Trojans, but also consume a significant amount of resources. This relates to network traffic, first of all, which is wholly controlled by various intelligent antiviruses and firewalls. The reason for writing this article was that traders complained of slowed MetaTrader 4 Client Terminal when working with Outpost Firewall. We decided to make our own research using Kaspersky Antivirus 6.0 and Outpost Firewall Pro 4.0.

As the library grows, its code must be optimized again in order to reduce its size. The version of the library described in this article has become even more object-oriented. This made the code easier to learn. A detailed description of the latest changes will allow the readers to develop the library independently based on their own needs.

This article is intended to get its readers acquainted with a possible variant of using graphical objects of the MQL5 language. It analyses an indicator, which implements a panel of managing a simple spectrum analyzer using the graphical objects. The article is meant for readers acquianted with basics of MQL5.

If you think automated systems are simple, then you probably don't fully understand what it takes to create them. In this article, we will talk about the problem that kills a lot of Expert Advisors. The indiscriminate triggering of orders is a possible solution to this problem.

Developing a system of SMS notifications that informs you of the status of your EA so that you are always aware of any critical situation, wherever you may be.

It may be news to many our readers that all preparations for writing an EA can be performed once and then used continuously.

This is the final article, devoted to transferring an indicator code into an Expert Advisor code. Here the author transforms on a certain example a code of an Expert Advisor so, that this EA is presented in a single file without calling custom indicators.

Estimation of statistical parameters of a sequence is very important, since most of mathematical models and methods are based on different assumptions. For example, normality of distribution law or dispersion value, or other parameters. Thus, when analyzing and forecasting of time series we need a simple and convenient tool that allows quickly and clearly estimating the main statistical parameters. The article shortly describes the simplest statistical parameters of a random sequence and several methods of its visual analysis. It offers the implementation of these methods in MQL5 and the methods of visualization of the result of calculations using the Gnuplot application.

The previous chapter of part VIII on graphical interfaces has focused on the elements of static and drop-down calendar. The second chapter will be dedicated to an equally complex element — a tree view, that is included in every complete library used for creating graphical interfaces. A tree view implemented in this article contains multiple flexible settings and modes, thus allowing to adjust this element of control to your needs.

Currently, the library is able to track standard graphical objects on the client terminal chart, including their removal and modification of some of their parameters. At the moment, it lacks the ability to create standard graphical objects from custom programs.

This article provides a method to create complex indicators while also avoiding the problems that arise when dealing with multiple plots, buffers and/or combining data from multiple sources.

In the previous articles, we started creating a large cross-platform library simplifying the development of programs for MetaTrader 5 and MetaTrader 4 platforms. In the fifth part of the article series, we created trading event classes and the event collection, from which the events are sent to the base object of the Engine library and the control program chart. In this part, we will let the library to work on netting accounts.