1. What is smart pointer, why will the smart pointer be invented? (10 pts.) 2. There're two kinds of smart pointers: unique ptr' and shared_ptr'. Please do a search online to discuss the difference of these two smart pointers. (20 pts.) 3. What header file is required when you try to use smart pointers? (10 pts.) 4. Discuss the difference among the containers: vector', forward list' and 'list' ifrom the perspective of data structure (20 pts.)