Question on Enum

Having problems understanding enum in C++.

Quote:

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There is an implicit conversion from any enum type to int. Suppose this type exists:

enum MyEnumType { ALPHA, BETA, GAMMA };

Then the following lines are legal:

int i = BETA; // give i a value of 1
int j = 3 + GAMMA; // give j a value of 5

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But what if I have two different enum types? Say

Code:

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enum MyEnumType { ALPHA, BETA, GAMMA };
enum SomeonesEnumType { ALPHA, SATURDAY, MONDAY };

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and these exist in a seperate class called "Enums".

if i were to type in my main.cpp,

Code:

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Enums::ALPHA;

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which enum would it choose?

I can't seem to find a way to specify which enum I would like to use (e.g. like in Java, I can just type Enums.MyEnumType.ALPHA and Enums.SomeonesEnumType.ALPHA

I didn't know that C++ allowed to use the constants inside an enumeration type without first defining a variable of that type...but I can answer your last question:

Code:

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enum MyEnumType { ALPHA, BETA, GAMMA };
MyEnumType x;

int i = x.ALPHA;

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This is how you specify what enumeration type you would like to use, by declaring a variable of that type.

I tried doing it like this:

Enums::MyEnumType x;
int i = x.ALPHA;

but it didn't work :(

The error was:

Program.cpp: 16: error: request for member 'ALPHA' in 'x', which is a non-class type 'Enums::MyEnumType'

EDIT: Okay, I just realised that I can't have two ALPHA. It will conflict. Whoops.

My compiler doesn't even let me compile enumerations that have the same identifiers, named or unnamed.

One solution I can think of is to use namespaces:

Code:

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#include <iostream>
namespace first {
    enum {VALUE = 1};
}
namespace second {
    enum {VALUE = 42};
}

int main()
{
    std::cout << first::VALUE << ' ' << second::VALUE << '\n';
    std::cin.get();
}

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