C++ (7) - new features in 11/14

Summarize the content of the new features of C++11/14 encountered, and add a new one when you encounter it.

1. auto variable

2、for(auto a: {1,2,3,4,5,6})

3. In STL:

New container types array, forward_list, Unordered_Set/Multiset, Unordered Map/Multimap