Re: find() of std::set

From:
Rolf Magnus <ramagnus@t-online.de>
Newsgroups:
comp.lang.c++
Date:
Mon, 10 Nov 2008 16:08:40 +0100
Message-ID:
<gf9ipp$ofm$03$1@news.t-online.com>
Christian Meier wrote:

Hello Newsgroup

I have a question about the find function of std::set.
When I have a "std::set<int*>", why can't I call the find() function with
an "const int*"? I know that


Because:

my key type is different from the type of the parameter I give to the find
function but can't the find() function be written in a way where
this would work?


I guess it could in theory. But it would mean that the class std::set would
have to be specialized just for this specific case.

Normally, "int*" can be compared with "const int*" without problems...
And as a follow-up question: What would you do in a function like this:

void MyClass::myFunc(const LargeObject* input)
{
    // ...
    // m_LargeObjectSet is a member variable of the class MyClass and has
the type "std::set<LargeObject*>". How would you write the following line?
const_const? Copy the large object?
    // m_LargeObjectSet.find(input);


    m_LargeObjectSet.find(const_cast<LargeObject*>(input));

    // ...
}

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