I have an std::vector like this
std::vector<std::pair<T,T>> xyz. xyz has a length of 10 and another function fills exactly 3 spots, say 4, 6, and 8 with std::pair<T,T>. While iterating through the vector, I want to know where the non-empty spots are there so that I can further work with the std::pair<T,T>s.
I think I can use c++17's std::optional<> but I am using c++14. Is there any way to find out the spots in an std::vector which are not empty in c++14.
the vector will look something like this after assignment from the function
index value
0:
1:
2:
3:
4: <7,8>
5:
6: <9,2>
7:
8: <8,6>
9:
I want to iterate over the above vector and only say print the std::pairs
You cannot do it if you don't do some work on your data-structure, for every element in vector is initialized.
The simplist and quickest way I think, is to store a std::vector<bool> of the same size to store whether a element is not only initialized, but "modified" later as well.
If you worry that you may forget to set the other vector, bind them together:
std::vector<std::pair<std::pair<int, int>, bool>> a;
If you still think this is too ugly, you may have to implement your own simple optional