声明枚举标识符的底层类型 [英] declaring the underlying type of enumeration identifier

问题描述

我已经声明了一个枚举如下：

I have declared an enum as follows:

enum fileType {typeA, typeB};

当我尝试将directoryType类型附加到字符串时，会导致错误。
我相信我需要在枚举声明中包含枚举标识符的基本类型。或类似

This is causing an error when I try to append directoryType type to a string. I believe I need to include the underlying type of the enumeration identifiers in the enum declaration. Or something like

enum fileType : string {typeA, typeB}; 

/library/2dzy4k6e(v=vs.80).aspxrel =nofollow> http://msdn.microsoft.com/en-us/library/2dzy4k6e（v = vs.80）.aspx

as described in http://msdn.microsoft.com/en-us/library/2dzy4k6e(v=vs.80).aspx

但是这不是为我编译。

however this is not compiling for me. What is the proper syntax for declaring the underlying type of enum identifiers?

推荐答案

您可能只有整数类型作为枚举的底层类型。这意味着签名和未签名的类型，如 char short int long 。

You may have only integral types as underlying type for enum. That means signed and unsigned types like char short int and long.

枚举名称无法在运行时使用。

The names of enumerations are nowhere available runtime. If you want to display them (or append to string) then you have to write special code.

 enum fileType {typeA, typeB};
 const char *fileType_str[]={ "typeA","typeB"};

 fileType x = typeA;
 // display x
 std::cout << "x is " << fileType_str[x] << std::endl;

 // append x to string
 std::string y = "directoryType type to a ";
 y += fileType_str[x];

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