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C++ getting round const

likeregularchickens · 2006-07-05T19:07:54

Hi, I had a phone interview the other day and there was a question that was something like 'if I have a const function, in which I obviously can't change any data, how do I get around this and change non-const data?' I'd never heard of this and it isn't in my teach yourself C++ in 21 days book. The answer was to use something but I can't remember it's name.... it began with mute.... i think. Can anyone tell me what this is? Thanks.

General and Gameplay Programming Programming

Started by likeregularchickens July 05, 2006 01:19 PM

10 comments, last by Will F 17 years, 9 months ago

ApochPiQ

23,138

July 05, 2006 06:05 PM

Quote:Original post by Fruny
Quote:Original post by ApochPiQ
This can also be done with aliasing, where multiple pointers/references point to a single object:
void SomeObject::ConstFunction(SomeObject& nonconstobj) const{   nonconstobj.member = value;}SomeObject foo;foo.ConstFunction(foo);
That's not really getting around anything, since you still need a non-const reference. The fact that you have a const member function, or even the fact that you have a member function at all is barely relevant. Except for accessing private members, I guess.

If I were to just give you a const Foo&, you'd be stuck.

This is true - but as long as a non-const Foo& is available somewhere, aliasing can still bypass constness to some extent. Yeah, the example's not so great, but I couldn't think of one that looks real-worldish and wasn't excessively long.

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