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Up: NOTE 167 AIPS++ Programming: STANDARDS AND GUIDELINES Previous: Documentation and Naming

Subsections

Coding

Forward Declarations

#include only those header files your class absolutely requires. Use forward declarations when that will suffice.¹⁴

Protected Data Members (`*`)

Avoid protected data members, using protected member functions for access to private data instead.

Access to Private Data

Do not return pointers or references to private data, except to accomodate Fortran or C libraries, or if efficiency absolutely requires it.¹⁵

Label All Virtual Functions Explicitly

Virtual functions in a derived class shall be explicitly labelled with the virtual keyword in the class declaration, even though this is not required by the language.

Document Loose Ends

Indicate unfinished or questionable code with the documentation extractor's tag <todo>.

Standard Class Member Functions

Provide definitions for all of the standard member functions which the compiler would (otherwise) generate automatically: default constructor¹⁶, destructor¹⁷, copy constructor, and the assignment operator. For any of these which you really wish to disallow, declare them private, and create minimal implementations (if any at all). For example:

   ...
   private:
      SomeClass () {;}   // disable the default constructor
   ...

The Order of Function Arguments

Functions shall be declared so that their arguments (parameters) appear in this order: output parameters first; input/output parameters next; input parameters last.¹⁸ Functions which return only one value should usually use the function's return-value to return that value, rather than add an additional output parameter to the parameter list. If a function modifies its single argument in place, then that argument is best understood as an input/output argument.¹⁹

Formal Arguments and Default Parameters

Specify formal arguments and default parameters in the function declaration; use the same names in the function definition.²⁰

One argument constructors

Constructors with one argument should be made explicit, or have an explanation why automatic conversion is wanted (as an example: Unit(String) is an obvious candidate for automatic conversion, to be able to write e.g. ``km/s'' rather than Unit(``km/s'')).

Return Types

Specify explicit return types for all functions. Return an appropriate integer value from main.

const Functions

All functions that do not change the state of the class should be declared const. If only the ``hidden'' state (like a cache) changes, the function should be declared const, but with a mutable cache variable. mutable should be used carefully.

Compound Statements

Multi-line compound statements should have braces. E.g.

if (condition) {
   statement1;
} else {
   statement2;
};