Articles on the MQL5 programming and use of technical indicators

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.

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.

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.

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.

The article considers the necessity and general principles of developing a bundled program that would contain both an Expert Advisor, a script and an indicator.

The article is concerned with the problem of re-counting of the indicator value in the MetaTrader 4 Client Terminal when the null bar changes. It outlines general idea of how to add to the indicator code some extra program items that allow to restore program code saved before multiple re-counting.

Creation of Custom Indicators in the MetaTrader trading system has a number of features.