Composite Assignment Operators for enums

[David Rasmussen]

Given an enum type E, how do I make, say, operator += work for that enum
type?

/David

 

[Alf P. Steinbach]

Given an enum type E, how do I make, say, operator += work for that enum
type?

Best to avoid enum types.

C++ is not Ada, as we have discussed before a few times... ;-)

But if you absolutely must,


E& operator += (E& lhs, E rhs )
{
lhs = static_cast<E>( lhs + rhs );
return lhs;
}

 

[David Rasmussen]

Best to avoid enum types.

I disagree. To me, it's like saying "it's best to avoid ints".

C++ is not Ada, as we have discussed before a few times... ;-)

But hopefully, C++ will learn something from Ada as time goes on.

But if you absolutely must,


E& operator += (E& lhs, E rhs )
{
lhs = static_cast<E>( lhs + rhs );
return lhs;
}

Thanks!

/David

 

[Thomas Matthews]

Given an enum type E, how do I make, say, operator += work for that enum
type?

/David

By converting the enum into a class or providing global functions
to perform the operation.

http://www.parashift.com/c++-faq-lite/newbie.html#faq-29.18
http://tinyurl.com/28ntu
http://cpptips.hyperformix.com/Enums.html
http://www.bearcave.com/software/java/misl/enum/type_safe_enum.html

You can get a lot of examples by typing "enumeration C++" into
your favorite search engine.

--
Thomas Matthews

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