![My First "Grail"](https://c.mql5.com/2/13/144_2.png)
![My First "Grail"](https://c.mql5.com/i/articles/overlay.png)
My First "Grail"
Examined are the most frequent mistakes that lead the first-time programmers to creation of a "super-moneymaking" (when tested) trading systems. Exemplary experts that show fantastic results in tester, but result in losses during real trading are presented.
![Considering Orders in a Large Program](https://c.mql5.com/2/13/114_3.gif)
![Considering Orders in a Large Program](https://c.mql5.com/i/articles/overlay.png)
Considering Orders in a Large Program
General principles of considering orders in a large and complex program are discussed.
![A Pause between Trades](https://c.mql5.com/2/12/103_1.gif)
![A Pause between Trades](https://c.mql5.com/i/articles/overlay.png)
A Pause between Trades
The article deals with the problem of how to arrange pauses between trade operations when a number of experts work on one МТ 4 Client Terminal. It is intended for users who have basic skills in both working with the terminal and programming in MQL 4.
![MagicNumber: "Magic" Identifier of the Order](https://c.mql5.com/2/13/105_2.gif)
![MagicNumber: "Magic" Identifier of the Order](https://c.mql5.com/i/articles/overlay.png)
MagicNumber: "Magic" Identifier of the Order
The article deals with the problem of conflict-free trading of several experts on the same МТ 4 Client Terminal. It "teaches" the expert to manage only "its own" orders without modifying or closing "someone else's" positions (opened manually or by other experts). The article was written for users who have basic skills of working with the terminal and programming in MQL 4.
![How to Use Crashlogs to Debug Your Own DLLs](https://c.mql5.com/2/13/153_6.gif)
![How to Use Crashlogs to Debug Your Own DLLs](https://c.mql5.com/i/articles/overlay.png)
How to Use Crashlogs to Debug Your Own DLLs
25 to 30% of all crashlogs received from users appear due to errors occurring when functions imported from custom dlls are executed.
![Working with Files. An Example of Important Market Events Visualization](https://c.mql5.com/2/13/112_2.gif)
![Working with Files. An Example of Important Market Events Visualization](https://c.mql5.com/i/articles/overlay.png)
Working with Files. An Example of Important Market Events Visualization
The article deals with the outlook of using MQL4 for more productive work at FOREX markets.
![Error 146 ("Trade context busy") and How to Deal with It](https://c.mql5.com/2/17/94_1.gif)
![Error 146 ("Trade context busy") and How to Deal with It](https://c.mql5.com/i/articles/overlay.png)
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.
![Information Storage and View](https://c.mql5.com/2/13/128_4.gif)
![Information Storage and View](https://c.mql5.com/i/articles/overlay.png)
Information Storage and View
The article deals with convenient and efficient methods of information storage and viewing. Alternatives to the terminal standard log file and the Comment() function are considered here.
![Genetic Algorithms: Mathematics](https://c.mql5.com/2/13/133_1.png)
![Genetic Algorithms: Mathematics](https://c.mql5.com/i/articles/overlay.png)
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.
![How to Evaluate the Expert Testing Results](https://c.mql5.com/2/13/125_2.gif)
![How to Evaluate the Expert Testing Results](https://c.mql5.com/i/articles/overlay.png)
How to Evaluate the Expert Testing Results
The article gives formulas and the calculation order for data shown in the Tester report.
![Requirements Applicable to Articles Offered for Publishing at MQL4.com](https://c.mql5.com/2/17/99_6.gif)
![Requirements Applicable to Articles Offered for Publishing at MQL4.com](https://c.mql5.com/i/articles/overlay.png)
Requirements Applicable to Articles Offered for Publishing at MQL4.com
Requirements Applicable to Articles Offered for Publishing at MQL4.com
![Expert Advisor Sample](https://c.mql5.com/2/17/82_1.gif)
![Expert Advisor Sample](https://c.mql5.com/i/articles/overlay.png)
Expert Advisor Sample
The principles of MQL4-programs development are shown on sample of creating a simple Expert Advisor system based on the standard MACD indicator.
![What the Numbers in the Expert Testing Report Mean](https://c.mql5.com/2/17/81_1.gif)
![What the Numbers in the Expert Testing Report Mean](https://c.mql5.com/i/articles/overlay.png)
What the Numbers in the Expert Testing Report Mean
Article explains how to read testing reports and to interpret the obtained results properly.
![Testing Features and Limits in MetaTrader 4](https://c.mql5.com/2/17/80_1.gif)
![Testing Features and Limits in MetaTrader 4](https://c.mql5.com/i/articles/overlay.png)
Testing Features and Limits in MetaTrader 4
This article allows to find out more about features and limits of Strategy Tester in MetaTrader 4.
![Strategy Tester: Modes of Modeling during Testing](https://c.mql5.com/2/17/78_7.gif)
![Strategy Tester: Modes of Modeling during Testing](https://c.mql5.com/i/articles/overlay.png)
Strategy Tester: Modes of Modeling during Testing
Many programs of technical analysis allow to test trading strategies on history data. In the most cases, the testing is conducted on already completed data without any attempts to model the trends within a price bar. It was made quickly, but not precisely
![Features of Custom Indicators Creation](https://c.mql5.com/2/16/77_1.gif)
![Features of Custom Indicators Creation](https://c.mql5.com/i/articles/overlay.png)
Features of Custom Indicators Creation
Creation of Custom Indicators in the MetaTrader trading system has a number of features.
![Features of Experts Advisors](https://c.mql5.com/2/16/76_2.gif)
![Features of Experts Advisors](https://c.mql5.com/i/articles/overlay.png)
Features of Experts Advisors
Creation of expert advisors in the MetaTrader trading system has a number of features.