Determine if map contains a value for a key?

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

Appending a vector to a vector

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:

How to sum up elements of a C++ vector?

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

Remove spaces from std::string in C++

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