explicit forward_list(const Allocator& = Allocator());
Effects: Constructs an empty forward_list object using the specified allocator.
Complexity: Constant.
explicit forward_list(size_type n);
Effects: Constructs a forward_list object with n value-initialized elements.
Requires: T shall be DefaultConstructible.
Complexity: Linear in n.
forward_list(size_type n, const T& value, const Allocator& = Allocator());
Effects: Constructs a forward_list object with n copies of value using the specified allocator.
Requires: T shall be CopyInsertable into *this.
Complexity: Linear in n.
template <class InputIterator>
forward_list(InputIterator first, InputIterator last, const Allocator& = Allocator());
Effects: Constructs a forward_list object equal to the range [first,last).
Complexity: Linear in distance(first, last).
template <class InputIterator>
void assign(InputIterator first, InputIterator last);
Effects: clear(); insert_after(before_begin(), first, last);
void assign(size_type n, const T& t);
Effects: clear(); insert_after(before_begin(), n, t);