Message from C, C++ talks
Well, std::vector is a template-based wrapper on dynamically allocated arrays, that you can resize dynamically, and use lots of things like alghorithms from STL. Also it has nice optimizations that go out of the box.
To use it you basically create an std::vector object giving it your type. Like
std::vector<int> is something like a dynamic array of int elements.
Then you can work with it as with any array via square brackets. Or use other things like iterators. You can get the current size of array calling
size function on it.
What else is not clear?