C++ enum definition scope

c++_enum.cc

#define DECLARE_ENUM(E) struct E { public: E(int value = 0) : _value((__Enum)value) { } E& operator=(int value) { this->_value = (__Enum)value; return *this; } operator int() const { return this->_value; } enum __Enum {
#define END_ENUM() }; private: __Enum _value; };

#include <iostream>

using namespace std;

class B {
    B &operator=(const B &);
};

class A {
B member;
};

DECLARE_ENUM(FileSystem)
Read = 0x1,
Write = 0x2
END_ENUM()

DECLARE_ENUM(DataBase)
Read = 0x1, 
Write = 0x2
END_ENUM()

int main() {
    FileSystem hello = FileSystem::Read;
    cout << hello << endl;
    return 0;
}