Effective STL clause 3

Ensure that objects in containers are copied correctly and efficiently

When using STL templates, we have to think about the issue of copying. If our custom type is stored in the STL. Some of the following issues may occur:

First of all

To prevent the copying process from becoming a bottleneck for the program, we chose to store the custom pointers. However, there is a problem with wild pointers, so we need to use smart pointer shared_pre to avoid them.

Then

If the storage type is a base class and we store derived classes at this point, a truncation occurs, that is, only the part of the base class is copied, and the derived class is partially lost.

At last

In contrast to arrays, Vector has its own unique bit, the most obvious is the dynamic growth of length.

Effective STL clause 3