Hi all,

I have a multimap, where key is an int and the value is a class. I can
insert into the multimap, but finding it difficult to retrieve the
value when keys match. I can do this with primitive types (int/char
etc).

Example:

class A {
public:
int vol;
int temp;
};

multimap<int, A> mechanics;
multimap<int, A>::iterator it;

A aobj;
aobj.vol=10;
aobj.temp=20;

mechanics.insert(pair<int, A>(5, aobj));
// many insert statements here....


std::pair<multimap<int,A>::iterator,multimap<int,A >::iterator> ret;

ret = mechanics.equal_range(5);

for (it=ret.first; it!=ret.second; ++it)
// How to read the object that matches the key in the multimap?
;


Upto this is okay, but then how can I find out the object
corresponding to the given key in the multimap?

Any /pointers?

Regards.

ambarish.mitra@gmail.com wrote:

> Hi all,
>
> I have a multimap, where key is an int and the value is a class. I can
> insert into the multimap, but finding it difficult to retrieve the
> value when keys match. I can do this with primitive types (int/char
> etc).

Strange. There is no difference when it comes to class types.


> Example:
>
> class A {
> public:
> int vol;
> int temp;
> };
>
> multimap<int, A> mechanics;
> multimap<int, A>::iterator it;
>
> A aobj;
> aobj.vol=10;
> aobj.temp=20;
>
> mechanics.insert(pair<int, A>(5, aobj));
> // many insert statements here....
>
>
> std::pair<multimap<int,A>::iterator,multimap<int,A >::iterator> ret;
>
> ret = mechanics.equal_range(5);
>
> for (it=ret.first; it!=ret.second; ++it)
> // How to read the object that matches the key in the multimap?

Did you try

it->second

;
[snip]


Best

Kai-Uwe Bux