14.4. C++ code style used

/*
    Copyright/license boilerplate
*/


// In header (.h) files:
#pragma once

#define ANY_MASTER_SWITCHES_FOR_FILE
#define DEBUG_A_SWITCH_THAT_SHOULD_BE_OFF_FOR_RELEASE_MODE

// In source (.cpp) files:
#include "myheader.h"

// Then:
#include <standard_library_file/in>
#include <zz_alphabetical/order>
#include <qt_libraries/in>
#include <zz_alphabetical/order>
#include "myproject/libraries/in"
#include "zz_alphabetical/order"

#ifdef SOME_MASTER_SWITCH
#include "conditional/include.h"
#endif

#define SOME_MACRO(x) x;  // but... really?

const QString SOME_CONSTANT;


namespace mynamespace {

// ... lower case so it's easy to distinguish Class::member from
//     namespace::member

// namespace contents NOT indented

}  // namespace mynamespace


class SomeClass {
    // Descriptive comments

    Q_OBJECT  // if applicable

public:
    // other classes and structs

public:
    SomeClass();
    // other constructors

    ~SomeClass();

    void someFunction();
    int& rFunctionReturningReference();

    // ...

protected:
    // functions

private:
    // functions

public:
    int public_member;  // e.g. for structs; no "m_"

private:
    int m_member_variable;  // perfectly clear

    static int s_static_variable;

    // NOT: int mMemberVariable;  // just because Stroustrup and Python habits
    // NOT: int memberVariable;  // helpful to have some indicator of membership
    // NOT: int member_;  // I hate this.

    char* m_pointedto;  // space AFTER the *; see Stroustrup
    char* m_p_pointedto;  // alternative notation; "_p_" for pointer
        // ... not usually necessary.

};


// ============================================================================
// Big divider
// ============================================================================

void SomeClass::someFunction(int param)
{
    // Indents are 4 spaces.

    int stack_variable;
    if (param > 1) {
        braceEvenForSingleStatement();
    }
    if (very_long_condition_1 && very_long_condition_2 &&
            very_long_condition_3 && very_long_condition_4) {
        // we indent the subsequent parts of the "if" statement once more.
    }

    auto someLambdaFunction = [](int param) -> void {
        statements;
    };
}


// ----------------------------------------------------------------------------
// Small divider
// ----------------------------------------------------------------------------

Note other popular coding standards:

C++

• Summary of my preferred style above:

  SomeClass, someFunction, some_variable, m_some_member_variable
  char* pointer_to_char;
  

• C++ Super-FAQ: https://isocpp.org/wiki/faq/coding-standards

• Stroustrup, http://www.stroustrup.com/bs_faq2.html#Hungarian

  some_variable
  const int* pointer;  // http://www.stroustrup.com/bs_faq2.html#whitespace
  
  some_function  // from the C++ book, anyway
  

• Qt coding style, https://wiki.qt.io/Qt_Coding_Style

  SomeClass, someFunction, someVariable, someMemberVariable
  char *pointerToChar;
  

• Google C++ Style Guide, https://google.github.io/styleguide/cppguide.html#Naming

  SomeClass, SomeFunction,
  some_stack_variable, some_member_variable_, kSomeConstantVariable
  

• https://chaste.cs.ox.ac.uk/trac/raw-attachment/wiki/CodingStandardsStrategy/codingStandards.pdf

  SomeClass, SomeFunction,
  some_stack_variable, mMemberVariable, mpMemberPointer, rReferenceArg,
  

• Boost, http://www.boost.org/development/requirements.html

  all_names_like_this
  

• GCC, https://gcc.gnu.org/codingconventions.html#Cxx_Names

  m_member
  s_static_member
  

• http://www.ivanism.com/Articles/CodingStandards.html

  SomeClass
  SomeNamespace
  SOME_CONSTANT
  SOME_MACRO(x)
  someMemberFunction
  SomeGlobalFunction
  m_someMemberVariable
  

Other languages

• C: Linux kernel style, https://kernel.org/doc/html/latest/process/coding-style.html

  char *linux_banner;
  char *some_function();
  

• Python, PEP8, https://www.python.org/dev/peps/pep-0008/; use Black (https://black.readthedocs.io/) with 79 characters per line.

Disabling compiler/linter warnings inline

• For example, compilers disagree on when a default: label should be included in a switch statement (https://github.com/quinoacomputing/quinoa/issues/158).

• For the Visual C++ compiler, an example is:

  #ifdef _MSC_VER  // Compiling under Microsoft Visual C++
  #pragma warning(push)
  #pragma warning(disable: 4100)  // C4100: 'app': unreferenced formal parameter
  #endif
  
  // problematic code here
  
  // ... and if we want to resume warnings for this compilation unit:
  #ifdef _MSC_VER  // Compiling under Microsoft Visual C++
  #pragma warning(pop)
  #endif
  

• For Qt Creator’s Clang-Tidy and Clazy, use Tools ‣ Options ‣ Analyzer, copy a starting configuration such as “Clang-Tidy and Clazy preselected checks [built-in]”, and edit it.