in discussing enum's, the example for a bool enum is given

enum State : bool { On = true, Off};

I get this error when I include this line in my main() function:
Error 1 error C3168: 'bool' : illegal underlying type for enum c:\documents and settings\<user snipped>\my documents\visual studio 2005\projects\c++\ex2_01a\ex2_01a\ex2_01a.cpp 20

Here's my MFC Console .cpp file:

#include "stdafx.h"
#include <iostream>
using namespace std;


int _tmain(int argc, _TCHAR* argv[])
{

enum State : bool {On=true, Off} myState;
myState = On;

//I try the std::cout line below, but it's not in the book
//but my compile error is on the "enum State : bool" line

std::cout << "state = " << (int)myState << std::endl;

return 0;
}



Sincerely,
Brian

__________________
Sincerely,
Brian

See your problem -i.e. I can duplicate it, but have not found a solution. I suggest emailing the author -and please post answer.

I don't know how to reach the author. Does Ivor state in the book that he is open to comments / questions?




Sincerely,
Brian

Go to http://www.wrox.com/WileyCDA/WroxTit...ew_errata.html

and fill in the form at
http://wrox.custhelp.com/cgi-bin/wro...nduser/ask.php

Btw the Errata page, linked to above, now lists some corrections.

Edit:
You may find the following Visual Studio forum useful, especially for the above problem.
http://forums.microsoft.com/msdn/sho...id=29&siteid=1

I contacted Wiley/Wrox about this, and they got this feedback from the auther, Ivor Horton.

Per the author:

>>The example on P. 62 is not correct. The enum with type bool enumerators should be:

enum State : bool {On=true, Off=false};

The original fragment used to compile but the compiler was ultimately modified to enforce the rule that enumerators in an enum of type bool must all be explicitly initialized. C++/CLI enums of other explicit types do not need to be initialized explicitly, although they can be.

Note that the section "Specifying the Type for Enumeration Constants" is misplaced and should be a subsection of the "C++/CLI Programming" section as it is specific to C++/CLI.Regular C++ only supports enums with an implicit integral type for the enumerators.<<


Sincerely,
Brian