Divisão de Observação da Terra e Geoinformática

Essa página está em modo somente de leitura. Você pode visualizar a fonte, mas não alterá-la. Informe-se com o administrador do Wiki, caso você ache que isso está incorreto.
====== Convenção de Programação ======
**Recomendações para programação em C++**. \\
Baseado em "//The Elements of C++ Style - T. Misfeldt, G. Bumgardner, A. Gray//"


====== Namespace ======
  * Usar sempre o namespace **TerraLib**
  * Usar sempre os namespaces externos explicitamente

===== Exemplo =====
<code cpp>
namespace TerraLib
{
  ....
  std::string myString = getName();
  ....
}
</code>

====== Preprocessador ======
  * Use '#include " ... "’ for collocated header files and '#include <...>' for external header files
  * Place preprocessor include guard (macros associadas a arquivos include) in header files
  * Use #if. . #endif and #if def . . #endif instead of "/* . . .*/" comments to hide blocks of code
  * Use macros sparingly
  * Do not use "#define" to define constants – declare static const variables instead

===== Example =====
<code cpp>
#ifndef TE_CONNECTION_POOL_H
#define TE_CONNECTION_POOL_H
....
static const float TeMaxFloat = 3.4e37;
....
#endif // end TE_CONNECTION_POOL_H
</code>



====== Declarações ======
  * Use typedefs to simplify complicated type expressions
  * Create a zero-valued enumerator to indicate an uninitialized, invalid, unspecified or default state
  * Do not define enumerations using macros or integer constants
  * Declare enumerations within a namespace or class

===== Example =====
<code cpp>
typedef std::pair<TeLine, double> TeLineLength;
typedef std::vector<lineLength> TeLineSizes;

enum TeSelectionMode
{
  TeSelectionModeDefault,	  //!< default selection
  TeSelectionModeTePointed,	  //!< object pointed
  TeSelectionModeTeQueried,	  //!< object queried
  TeSelectionModeTePointedQueried //!< object pointed and queried
}
</code>


====== Escopo ======
  * Declare for-loop iteration variables inside of for statements
===== Example =====
<code cpp>
for (int i = 0; i < 10; i++)
</code>


====== Funções e Métodos ======
  * Use an enumeration instead of a Boolean to improve readability
  * Use an object pointer instead of a reference if a function stores a reference or pointer to the object
  * Accept objects by reference and primitive or pointer types by value

  * Pass enumerator values, not integer constants
  * Do not use void* in a public interface
  * Use inline functions instead of macros
  * Inline only the simplest of functions


====== Classes ======
  * Define small classes and small methods
  * Declare the access level of all members
  * Declare all member variables private
  * Avoid the use of friend declarations


====== Membros de Classes ======

  * Declare an explicit default constructor for added clarity
  * Always declare a copy constructor, assignment operator, and destructor if the class can be instantiated
  * Always implement a virtual destructor if your class may be subclassed
  * Make constructors protected to prohibit direct instantiation
  *  Make constructors private to prohibit derivation
  * Declare a private operator new() to prohibit dynamic allocation
  * Declare a protected or private destructor to prohibit static or automatic allocation
  * Declare single-parameter constructors as explicit to avoid unexpected type conversions
  * Use default arguments to reduce the number of constructors
  * Do not overload non-virtual methods in subclasses
  * Declare virtual methods protected and call them from public non-virtual methods
  * Keep your functions “const-correct"
  * Use object pointers and references in class declarations


====== Operadores ======

  * Adhere to the natural semantics of operators
  * Do not overload operator&&() or operator||()
  * Invoke the superclass assignment operator(s) in the assignment operator of a subclass
  * Implement copy-safe and exception-safe assignment operators
  * Define binary operators outside of a class
  * Implement a Boolean operator in terms of its opposite




====== Templates ======

  * Use templates instead of macros to create parameterized code
  * Do not use const or volatile qualified types as template parameters

===== Exemplo =====
<code cpp>
// Example of bad macro
#define MAX(a,b) ( ((a) > (b)) ? (a) : (b) )

// Use template instead
template<class T>
inline T max (const T& a, const T& b)
{
  return (a > b) ? a : b/
}
</code>




====== Segurança, Cast e Conversões de Tipos ======

  * Use C++ casting operators instead of C-style casts. Ex:<code cpp>
short a = 2000;
int b;
b = (int) a;    // c-like cast notation - Ok only for fundamental data types

double d = 3.14159265;
int i = static_cast<int>(d); // No need for this cast
</code>
  * Avoid type casting and do not force others to use it.
  * Use **static-cast<>** to impose non-intuitive implicit conversions
  * Do not use reinterpret-cast<> in portable code
  * Only use **const-cast<>** on "this" or when dealing with non-const-correct code
  * Never use **dynamic-cast<>** as a substitute for polymorphism
  * Use **dynamic-cast<>** to restore lost type information
  * Always treat string literals as **const char***
  * Use C++ streams instead of stdio function for type safety. Exemplo: <code cpp>
const char* myMessage = "Hello World!!!"; // A string literal

printf("%s", myMessage); // Stdio function
std::cout << myMessage << std::endl; // Use this instead
</code>
  * Test all type conversions



====== Inicialização e Construção ======

  * Initialize all variables
  * Do not rely on the order of initialization of global objects
  * Always construct objects in a valid state
  * Initialize member variables in the initializer list
  * Initialize member variables in the order they are declared
  * Indicate when the declaration order of data members is significant
  * Always list any superclass constructors in the initialize list of a subclass constructor
  * Do not call virtual functions in constructors and destructors
  * Declare and initialize static variables within functions
  * Zero pointers after deletion
  * Use the **new** and **delete** operators instead of **malloc()** and **free()**



====== Declarações e Expressões ======

  * Do not rely on operator precedence in complex expressions
  * Use block statements in control flow constructs
  * Do not test for equality with true
  * Replace repeated non-trivial expressions with equivalent methods
  * Use **size-t** variables for simple loop iteration and array subscripts
  * Use a dummy template function to eliminate warnings for unused variables



====== Fluxo de Controle ======

  * Avoid **break** and **continue** in iteration statements
  * Avoid multiple **return** statements in functions
  * Do not use **goto**
  * Do not use **try .. throw .. catch** to manage control flow
  * Never use **setjmp()** or **longjmp()** in a C++ program
  * Always code a **break** statement in the last case of a switch statement



====== Manipulação de Erros e Exceções ======
  * Use return codes to report unexpected state changes
  * Use assertions to enforce a programming contract
  * Do not silently absorb or ignore unexpected runtime errors
  * Use assertions to report unexpected or unhandled runtime errors
  * Use exceptions to report errors that may occur under normal program execution
  * Manage resources with RAII for exception safety
  * Catch exceptions by reference, not by value
  * Do not discard exception information if you throw a new exception within a **catch** block
  * Avoid throwing exceptions in destructors


====== Eficiência ======
  * Use lazy evaluation and initialization
  * Reuse objects to avoid reallocation
  * Leave optimization for last