gruenedd@idmt.fraunhofer.de ha escrito:
Joaquín Mª López Muñoz wrote:
c.insert(std::make_pair(0,1)); c.insert(std::make_pair(1,0)); c.insert(std::make_pair(1,1)); c.swap_keys(c.begin(),++c.begin()); // would yield a duplicate element (1,1)
... it implies that a possible outcome of swap_keys() is that both elements get deleted
That`s what i would expect here. :] Now, why is this surprising? Consider the following snippet:
multi_index_container<int> c; // default "set"-like c.insert(1); c.insert(2); c.modify_key(--c.end(), _1 = 1);
Isn`t it "surprising" in the same way, that c.size() == 1? ;-)
Yep, well. I don't know, swap_keys's very name seems to indicate it'll follow std::swap semantics, which certainly doesn't have elimination of swapped elements as a possibility. Anyway, the other two reasons I gave for not providing this feature have more weight in my decision. Joaquín M López Muñoz Telefónica, Investigación y Desarrollo