Finding appropriate container type

Question

I need a container which has key value access(like map or unsorted map) but also can be sorted with some way.
Could someone suggest such container?
Example:
I need to store in it for example Employer class value as value and some string id as key which is not equal employer's name.
so I want container be sortable by employer name.

Well, `std::map` *is* sorted "in some way" (ie. according to its keys). If that's not what you want, please make your question clearer. — syam, Aug 21 '13 at 11:52
@syam I know that map is sorted by key but such sorting don't fit me. — Ruslan F., Aug 21 '13 at 11:56
Did you take a look at boost multi index container? http://www.boost.org/doc/libs/1_54_0/libs/multi_index/doc/index.html. Could be what you are looking for. — mkaes, Aug 21 '13 at 11:57

score 2 · Accepted Answer · answered Aug 21 '13 at 11:58

I suggest to use a plain std::map, e.g.

typedef std::map<std::string, Employer> EmployerMap;
EmployerMap employers;

...and then use some sequence container (e.g. a std::vector) with iterators pointing into the map. Then you sort the sequence container according to your needs:

// Build vector of iterators into map
std::vector<EmployerMap::iterator> v;
v.reserve( employers.size() );
for ( EmployerMap::iterator it, it != employers.end(); ++it ) {
  v.push_back( it );
}

// Sort vector by names of employers.
std::sort( v.begin(), v.end(),
           [](const EmployerMap::iterator &a, const EmployerMap::iterator &b) -> bool {
               return a->name < b->name;
           }
         );

Finding appropriate container type

1 Answers1