Initializing a static std::map in C++
Using C++11: Using Boost.Assign:
Using C++11: Using Boost.Assign:
Does something along these lines exist? No. With the stl map class, you use ::find() to search the map, and compare the returned iterator to std::map::end() so Obviously you can write your own getValue() routine if you want (also in C++, there is no reason to use out), but I would suspect that once you get the hang of using std::map::find() you won’t … Read more
or The second variant is a more generically applicable solution, as b could also be an array. However, it requires C++11. If you want to work with user-defined types, use ADL:
Here is the complete source code, updated from your source:
Actually there are quite a few methods. C++03 Classic for loop: for(std::vector<int>::iterator it = vector.begin(); it != vector.end(); ++it) sum_of_elems += *it; Using a standard algorithm: #include <numeric> sum_of_elems = std::accumulate(vector.begin(), vector.end(), 0); Important Note: The last argument’s type is used not just for the initial value, but for the type of the result as well. If you … Read more
It’s an O(N) operation to construct the new vector, but there isn’t really a better way.
I agree with R. Pate and Todd Gardner; a std::set might be a good idea here. Even if you’re stuck using vectors, if you have enough duplicates, you might be better off creating a set to do the dirty work. Let’s compare three approaches: Just using vector, sort + unique Convert to set (manually) Convert to set (using a constructor) … Read more
he typical way to check for existence in many STL containers such as std::map, std::set, … is:
The best thing to do is to use the algorithm remove_if and isspace: Now the algorithm itself can’t change the container(only modify the values), so it actually shuffles the values around and returns a pointer to where the end now should be. So we have to call string::erase to actually modify the length of the container: We … Read more
const_iterators don’t allow you to change the values that they point to, regular iterators do. As with all things in C++, always prefer const, unless there’s a good reason to use regular iterators (i.e. you want to use the fact that they’re not const to change the pointed-to value).