Changing the External Parameters of MQL4 Programs without Restarting

admin — Tue, 24 Nov 2009 10:34:17 +0000

Anybody who has ever launched an EA or an indicator for execution, faced the possibility to preliminarily set up external parameters that often underlay the success of the program. There is a possibility to change parameters during the program operation. But how can that be done without initialization? In some cases, this may affect managing the previously opened orders. In this article, we try to solve this problem as flexibly as possible.

Problem Statement

We will consider this problem for Expert Advisors rather than for indicators. For indicators, this problem is not so acute, although the methods are universal and you can apply them to any programs.

In the classical EA writing, the context must be created at every tick. There can be two kinds of contexts – the context of status and trading context. The context of status contains the current states of indicators and other elements underlying the decision making on opening/closing/modifying orders. Trading context contains the information about open orders, their statuses and quantities. After trading context has been analyzed, traders make decisions about what to do with their orders. Contexts are divided by types conditionally. This classification has been introduced for convenience.

To read the full article, please visit: http://articles.mql4.com/724

Working with Doubles in MQL4

admin — Wed, 11 Nov 2009 02:58:12 +0000

The MQL programming opens new opportunities for the automated trading, many people all over the world already have appreciated it.

When we are writing an Expert Advisor for trading, we must be sure that it will work correctly.

Many newbies often have some questions when the results of some mathematical calculations differ from those expected. The program is compiled and can work, but not as it should. They are checking the code again and again, finding the new “mistakes” in language, in implementation, in functions, etc.

In the most of cases, the careful analysis shows that the language and compiler work correctly, but code has a small error, and it can take a long time to find and correct it.

In this note we will consider a typical programming errors, that occurs while working with double numbers in MQL4 programs.

To read the full article, please visit: http://articles.mql4.com/866

MetaTrader Australia » MQL4 programs

Changing the External Parameters of MQL4 Programs without Restarting

Problem Statement

Working with Doubles in MQL4