Re: What is wrong with reference into std::map?

"Jim Langston" <>
Sun, 14 May 2006 11:52:43 -0700
"Phlip" <> wrote in message

Jim Langston wrote:

    it = MyMap.insert( MyMap.end(), std::make_pair< unsigned int,
std::string >( ID, std::string() ) );

Could you break up all these long lines, pleeeeze? Start with

typedef std::make_pair< unsigned int, std::string > mapType;

then use that everywhere you copied in that whole gizmo.

Yeah, well, the problem is I'm using a number of maps, 4, and I would have
to do that for every map since they're different pair types. By the time I
typedefed the maps, the iterators and the make pairs that's 12 different
things I have to remember what is what.

It's just easier for me to type them in so I don't have to keep going back
and seeing what they are.

Hmm.. so how do you assign a reference that has already been initialized?

int& MyRef = int1;
Who do I do to get MyRef to point to int2 now? Or can I?

You can't reseat a reference. That's a feature. You said "point to", which
betrays you think of a reference as a kind of pointer. It's really another
name for something; an alias.

Will a map let you use iterators? Some containers invalidate their
iterators after an insert, but I can't think of a technical reason for a
binary tree to do that, and maps generally implement as binary trees.

Well, I'm only using the reference after the insert to set the data, then I
don't use it anymore. The reference may be invalidated after another
insert, I'm not sure.

Well, I came across this problem and figured out that by putting brackets
around the whole thing the problem went away, I just wanted to know what the
problem was before I converted it into a function.

I'm goign to have to remember that you can't reset a reference. Dang, I
hope they add that to the language. Even if it takes another keyword.

std::reseat MyRef = int2;
MyRef<std::reseat> = int2;
std::reseat<int&>( MyRef ) = int2;

any format

 Phlip <-- NOT a blog!!!

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