Re: STL and finding objects by name

Barry <>
Fri, 4 Apr 2008 13:32:12 CST
On Apr 4, 9:37 pm, Matthew Bucknall <> wrote:


Apologies if the answer to this is obvious, I have spent quite some time
trying to come up with a solution. I would like to use some sorted STL
container (maybe a set ?) to hold a bunch of named objects, that is,
objects that posses their own name. I then want to search for objects in
the container by name. Here is an example:

class Thing

        Thing(const std::string& name):

        std::string get_name() const { return m_name; }

           // return const reference to avoiding copying.
           std::string const& get_name() const { return m_name; }

        bool operator< (const Thing& rhs) const
                return m_name < rhs.m_name;

           // provide operator== to meet the requirement of set
           bool operator== (Thing const& rhs) const { return m_name ==
rhs.m_name; }


        const std::string m_name;

           // remove const, to make Thing Assignable to meet the
requirement for container.
           // as long as you don't provide modifier, the class remains
           std::string m_name;


std::set<Thing> things;

std::set<Thing>::iterator find_thing(const std::string& name)
        // this won't work of course, but this hopefully illustrates
        // what I want to do

        return things.find(name);


a test case

#include <iostream>

int main()
     std::set<Thing>::iterator i = find_thing("hello");
     if (i != things.end())
         std::cout << i->get_name() << std::endl;


My question is, how can named objects (such as Thing) be stored in an
STL container such that they can then be efficiently found by name?
Note, I want named objects to have direct access to their name so
storing objects in a std::map<std::string, Thing> is no good IMHO
because items contained in the map don't have access to their keys.

I guess you meant bidirectional map,

check out Boost.Bimap, which is newly added into boost_1.35.0


Best Regards

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