C++核心準(zhǔn)則Enum.1: 枚舉類型比宏定義好

Enum.1: Prefer enumerations over macros

Enum.1:?枚舉類型比宏定義好

Reason(原因)

Macros do not obey scope and type rules. Also, macro names are removed during preprocessing and so usually don't appear in tools like debuggers.

宏定義不需要遵守范圍和類型規(guī)則。同時，宏定義名稱會在預(yù)編譯極端被替換因此通常也不會出現(xiàn)在調(diào)試器等工具中。

Example(示例)

First some bad old code:

首先是一些不好的老式代碼：

// webcolors.h (third party header)
#define RED   0xFF0000
#define GREEN 0x00FF00
#define BLUE  0x0000FF

// productinfo.h
// The following define product subtypes based on color
#define RED    0
#define PURPLE 1
#define BLUE   2

int webby = BLUE;   // webby == 2; probably not what was desired

Instead use an?enum:

使用枚舉替代：

enum class Web_color { red = 0xFF0000, green = 0x00FF00, blue = 0x0000FF };
enum class Product_info { red = 0, purple = 1, blue = 2 };

int webby = blue;   // error: be specific
Web_color webby = Web_color::blue;

We used an?enum class?to avoid name clashes.

我們可以使用枚舉類來避免名稱沖突。

Enforcement(實(shí)施建議)

Flag macros that define integer values.

標(biāo)記整數(shù)類型的宏定義。

原文鏈接：

https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#enum1-prefer-enumerations-over-macros

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