Warning: You are not allowed to use:
1. any static variables
2. any variables which is not inside a function
3. malloc and free
But this time, you have to implement a intact Iterator.
member function of Vector:
erase: erase elements which is pointed by begin to end ([begin,end)). While begin is equal to end, do not erase any elements.
insert: insert elements at position pos. The insert elements are from iterators which are pointed by begin to end ([begin,end)). While begin is equal to end, do not insert any elements.
Input is a sequence of non-negative integer (smaller than 100).
Complete Vector (constructor, destructor, begin, end, erase, insert, push_back and reserve) and Iterator (all data member functions).