iterate through unordered_map using boost_foreach

Question

In my class I've got such soundmap

class SoundSubSystem
{
private:
    boost::unordered_map<string, ISoundEngine*> soundmap;
....
};

But how to iterate through it using BOOST_FOREACH?

SoundSubSystem::~SoundSubSystem()
{
    BOOST_FOREACH(/*?*/ item, soundmap) {
        item.second->drop();
    }
};

What value type should item have?

Just as an advice, consider upgrading your compiler to a version that offers C++11 support, and use a range-based `for` loop: `for (auto& item : soundmap) { item.second->drop(); }`. — Andy Prowl, Jan 18 '14 at 16:04
I'm using visual studio 2010 - as far as I know it does not support c++11 — lapots, Jan 18 '14 at 16:09
Indeed it does not support C++11's range-based `for` loop, but it does support `auto`. So you can do: `BOOST_FOREACH(auto& item, soundmap) { item.second->drop(); }`. — Andy Prowl, Jan 18 '14 at 16:11

P0W · Accepted Answer · 2014-01-18T16:57:49.930

2

Try this :-

typedef boost::unordered_map<string, ISoundEngine*> myhash;

BOOST_FOREACH(myhash::value_type& item, soundmap) {
        item.second->drop();
    }

edited Jan 18 '14 at 16:57

answered Jan 18 '14 at 16:00

P0W

@user1432980 Could you try it with `typename` keyword. I wonder if `BOOST_FOREACH` macro might need that for such type. OR can use `auto` as suggested in one of the comment – P0W Jan 18 '14 at 16:22
3

I'm afraid the problem here is with the comma that separates `string` from `ISoundEngine*`. Remember `BOOST_FOREACH` is a macro, so the `, ISoundEngine* ...` part will likely be interpreted as a second argument - I think. Rather use `BOOST_FOREACH(auto& item, soundmap)` or, if you really want to go the C++03 way, define a `typedef` for `boost::unordered_map` or `boost::unordered_map::value_type` outside the macro. – Andy Prowl Jan 18 '14 at 16:43

1 Answers1