C++核心准则Enum.3:枚举类​要比普通的枚举类型好

Enum.3: Prefer class enums over "plain" enums

Enum.3:枚举类要比普通的枚举类型好

Reason(原因)

To minimize surprises: traditional enums convert to int too readily.

尽量减少意外性：经典的枚举类型太容易转换为整数了。

Example(示例)

void Print_color(int color);

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

Web_color webby = Web_color::blue;

// Clearly at least one of these calls is buggy.
Print_color(webby);
Print_color(Product_info::blue);

Instead use an enum class:

而使用枚举类的时候：

void Print_color(int color);

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

Web_color webby = Web_color::blue;
Print_color(webby);  // Error: cannot convert Web_color to int.
Print_color(Product_info::red);  // Error: cannot convert Product_info to int.

Enforcement(示例)

(Simple) Warn on any non-class enum definition.

(简单)警告所有枚举类以外的枚举定义。

原文链接：

https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#enum3-prefer-class-enums-over-plain-enums

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