Re: Modifying the value of key of a map.

Hi,

I have a map of the type:

std::map<A, B> mymap_A;
std::map<X, A> mymap_X;

where A, B and X are user defined types (i.e. my own clases)

At the beging of the program i do a insert on the maps. Later, at some
point i come across a situation where the value of some member of A
changes. e.g:

class A {
int a_member;
};

when i did an insert a_member was 2; now it is supposed to be 4.

Problem:

my first, and absolutely naive approach was:

std::map<A,B>::iterator i = mymap.find(valueofkey);
i->first = 4;

But this is not allowed as i->first is read only.

Now, the possible solution for this would be to either create a new
pair (and necessarily copy everything in the value part... which is
going to be very costly) and delete old and insert new pair.

Am I missing something too obvious??

Any pointers??

Thnx.
~M