# Coding Rules (Mostly inherited from IT++)

In the following sections we describe the naming conventions which are used for files, classes, structures, local variables, and global variables.

## Default Naming Rules for Variables

Generally, variables are named using lower-case letters and words are separated using under-score. But there are many exceptions, for instance abbreviations or classical matematical notations. Therefore, coding rules for variables are quite free. Examples:

- ``FFT_size'`
- ``initial_RV'`
- ``my_variable'`

## Default Naming Rules for Files

Files are named using lower-case letters and words are separated using under-score. If an abbreviation is inevitable within file name, it is written with lower-case letters.

Source files are named using ``.cpp'` suffix, whereas header files end with ``.h'` extension. Examples:

- ``my_file.h'`
- ``user_info.cpp'`

## Form of the source files

For all the library classes, both header file `[filename].h' and source file `[filename].cpp' should be implemented. And the following few rules should be respected

- if possible, each `#include ... ' dircetive should be located within the `.h' file, one obvious exception is the case of `#include "[filename].h"' written in `[filename].cpp'

- firstly, system headers should be included (i.e. those with brackets `#include <system_header_name>'), other headers (like `#include "my_header_name.h"') should follow (this rule leads to the faster search of an error on some compilators)

- source code itself should be placed in the `.cpp' file, `.h' should contains only class declarations and documentation (this rule has a few exceptions like inline functions, templates and some extremely short function bodies)

Rules considering formatting of the source code itself are stored in the file /system/astylerc, which is a configuration file for code formating utility named ASTYLE. To apply them, download the proper version from its web page http://astyle.sourceforge.net/

## Default Naming Rules for Functions

Function names are named using lower-case letters and words are separated using under-score. Abbreviations, when used in function names, are also written with lower-case letters. This rule applies both to stand-alone functions as well as to member functions of classes. Example:

- `int my_function_name(int a, int b)`

## Convention for sensitive functions

For efficiency, some functions may return pointers to internal variables. Such functionality is indicated by underscore as the first letter in the the name.

- `mat* _internal_matrix()`

## Default Naming Rules for Classes and Structures

Each new word in a class or structure name should always start with a capital letter and the words should not be separated. Abbreviations are written with capital letters. Examples:

- ``MyClassName'`
- ``MyStructName'`
- ``OFDM'`

## Default Functionality of Classes

All classes that are configured by input parameters should include:

- default empty constructor
- one or more additional constructor(s) that takes input parameters and initializes the class instance
- setup function, preferably named ``setup'` or ``set_parameters'`

Explicit destructor functions are not required, unless they are needed. It shall not be possible to use any of the other member functions unless the class has been properly initiated with the input parameters.