Doubt in STL map

[glathaa]

Hi,

Is it possible to have a structure as a key in stl-map?

Let us consider the following declaration.

struct key {
int a;
int b;
};

struct compare {
bool operator()(const struct key k1, const struct key k2) const {
return ((k1->a < k2->a) && (k2->a < k2->b));
}
};

map<struct key, float, compare> mymap;

Is this declaration correct? will it work correctly?

Thanks for your response.

-Latha

 

[jstreich]

I am unsure if that will work, but yes, the key can be any type including a struct. My understanding is that unless other wise told, the sort will use the types < operator... Granted I don't often play with maps, but simply writing a bool operator<(key,key) function should work without writting a compare.