22 Containers library [containers]

22.2 Container requirements [container.requirements]

22.2.3 Sequence containers [sequence.reqmts]

Table 78: Optional sequence container operations [tab:container.seq.opt]

🔗	Expression	Return type	Operational semantics	Container
🔗	a.front()	reference; const_reference for constant a	*a.begin()	basic_string, array, deque, forward_list, list, vector
🔗	a.back()	reference; const_reference for constant a	{ auto tmp = a.end(); --tmp; return *tmp; }	basic_string, array, deque, list, vector
🔗	a.emplace_front(args)	reference	Effects: Prepends an object of type T constructed with std::forward<Args>(args).... Preconditions: T is Cpp17EmplaceConstructible into X from args. Returns: a.front().	deque, forward_list, list
🔗	a.emplace_back(args)	reference	Effects: Appends an object of type T constructed with std::forward<Args>(args).... Preconditions: T is Cpp17EmplaceConstructible into X from args. For vector, T is also Cpp17MoveInsertable into X. Returns: a.back().	deque, list, vector
🔗	a.push_front(t)	void	Effects: Prepends a copy of t. Preconditions: T is Cpp17CopyInsertable into X.	deque, forward_list, list
🔗	a.push_front(rv)	void	Effects: Prepends a copy of rv. Preconditions: T is Cpp17MoveInsertable into X.	deque, forward_list, list
🔗	a.push_back(t)	void	Effects: Appends a copy of t. Preconditions: T is Cpp17CopyInsertable into X.	basic_string, deque, list, vector
🔗	a.push_back(rv)	void	Effects: Appends a copy of rv. Preconditions: T is Cpp17MoveInsertable into X.	basic_string, deque, list, vector
🔗	a.pop_front()	void	Effects: Destroys the first element. Preconditions: a.empty() is false.	deque, forward_list, list
🔗	a.pop_back()	void	Effects: Destroys the last element. Preconditions: a.empty() is false.	basic_string, deque, list, vector
🔗	a[n]	reference; const_reference for constant a	*(a.begin() + n)	basic_string, array, deque, vector
🔗	a.at(n)	reference; const_reference for constant a	*(a.begin() + n)	basic_string, array, deque, vector