问题
I have declared an enum as follows:
enum fileType {typeA, typeB};
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};
as described in http://msdn.microsoft.com/en-us/library/2dzy4k6e(v=vs.80).aspx
however this is not compiling for me. What is the proper syntax for declaring the underlying type of enum identifiers?
回答1:
You may have only integral types as underlying type for enum. That means signed and unsigned types like char short int and long.
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];
来源：https://stackoverflow.com/questions/12557164/declaring-the-underlying-type-of-enumeration-identifier