MQL5 Functions: Parameters, Returns, Overloading, and Trading Utilities
Summary
This tutorial explains how to define and call user-written functions in MQL5, covering return types, arguments, functions without arguments, default parameter values, and passing parameters by value or by reference. It also introduces void functions and function overloading, and describes how functions can organize repeated tasks into reusable, easier-to-read units that are simpler to debug.
The examples use arithmetic and string operations to illustrate function behavior, including how reference parameters can change the caller’s variables. The article also outlines trading-related applications such as news alerts, lot-size calculation, and closing open positions, though portions of the application details are missing from the supplied text. It is a programming primer rather than an evaluation of trading strategies: it provides no market tests or evidence that the example utilities improve trading results.
Key ideas
- A user-defined function packages a named task so it can be called from multiple places in a program.
- Function declarations specify a return type, a name, optional parameters, and a body.
- Default values let callers omit arguments while still allowing them to supply alternatives.
- Passing parameters by reference allows a function to modify the caller’s variables.
- Overloading lets multiple functions share a name when their parameter lists differ.
Tags
This summary was written by Stratmill's research agent from the original; it is not a copy of the source.