std::vector - Man Page

typedef _Alloc allocator_type
typedef __gnu_cxx::__normal_iterator< const_pointer, vector > const_iterator
typedef _Alloc_traits::const_pointer const_pointer
typedef _Alloc_traits::const_reference const_reference
typedef std::reverse_iterator< const_iterator > const_reverse_iterator
typedef ptrdiff_t difference_type
typedef __gnu_cxx::__normal_iterator< pointer, vector > iterator
typedef _Base::pointer pointer
typedef _Alloc_traits::reference reference
typedef std::reverse_iterator< iterator > reverse_iterator
typedef size_t size_type
typedef _Tp value_type

vector ()=default
Creates a vector with no elements.
template<typename _InputIterator , typename  = std::_RequireInputIter<_InputIterator>> constexpr vector (_InputIterator __first, _InputIterator __last, const allocator_type &__a=allocator_type())
Builds a vector from a range.
constexpr vector (const allocator_type &__a) noexcept
Creates a vector with no elements.
constexpr vector (const vector &__x)
Vector copy constructor.
constexpr vector (const vector &__x, const __type_identity_t< allocator_type > &__a)
Copy constructor with alternative allocator.
constexpr vector (initializer_list< value_type > __l, const allocator_type &__a=allocator_type())
Builds a vector from an initializer list.
constexpr vector (size_type __n, const allocator_type &__a=allocator_type())
Creates a vector with default constructed elements.
constexpr vector (size_type __n, const value_type &__value, const allocator_type &__a=allocator_type())
Creates a vector with copies of an exemplar element.
vector (vector &&) noexcept=default
Vector move constructor.
constexpr vector (vector &&__rv, const __type_identity_t< allocator_type > &__m) noexcept(noexcept(vector(std::declval< vector && >(), std::declval< const allocator_type & >(), std::declval< typename _Alloc_traits::is_always_equal >())))
Move constructor with alternative allocator.
constexpr ~vector () noexcept
template<typename... _Args> constexpr auto _M_emplace_aux (const_iterator __position, _Args &&... __args) -> iterator
template<typename _InputIterator , typename  = std::_RequireInputIter<_InputIterator>> constexpr void assign (_InputIterator __first, _InputIterator __last)
Assigns a range to a vector.
constexpr void assign (initializer_list< value_type > __l)
Assigns an initializer list to a vector.
constexpr void assign (size_type __n, const value_type &__val)
Assigns a given value to a vector.
constexpr reference at (size_type __n)
Provides access to the data contained in the vector.
constexpr const_reference at (size_type __n) const
Provides access to the data contained in the vector.
constexpr const_reference back () const noexcept
constexpr reference back () noexcept
constexpr const_iterator begin () const noexcept
constexpr iterator begin () noexcept
constexpr size_type capacity () const noexcept
constexpr const_iterator cbegin () const noexcept
constexpr const_iterator cend () const noexcept
constexpr void clear () noexcept
constexpr const_reverse_iterator crbegin () const noexcept
constexpr const_reverse_iterator crend () const noexcept
constexpr const _Tp * data () const noexcept
constexpr _Tp * data () noexcept
template<typename... _Args> constexpr iterator emplace (const_iterator __position, _Args &&... __args)
Inserts an object in vector before specified iterator.
template<typename... _Args> constexpr reference emplace_back (_Args &&... __args)
constexpr bool empty () const noexcept
constexpr const_iterator end () const noexcept
constexpr iterator end () noexcept
constexpr iterator erase (const_iterator __first, const_iterator __last)
Remove a range of elements.
constexpr iterator erase (const_iterator __position)
Remove element at given position.
constexpr const_reference front () const noexcept
constexpr reference front () noexcept
constexpr allocator_type get_allocator () const noexcept
Get a copy of the memory allocation object.
template<typename _InputIterator , typename  = std::_RequireInputIter<_InputIterator>> constexpr iterator insert (const_iterator __position, _InputIterator __first, _InputIterator __last)
Inserts a range into the vector.
constexpr iterator insert (const_iterator __position, const value_type &__x)
Inserts given value into vector before specified iterator.
constexpr iterator insert (const_iterator __position, initializer_list< value_type > __l)
Inserts an initializer_list into the vector.
constexpr iterator insert (const_iterator __position, size_type __n, const value_type &__x)
Inserts a number of copies of given data into the vector.
constexpr iterator insert (const_iterator __position, value_type &&__x)
Inserts given rvalue into vector before specified iterator.
constexpr size_type max_size () const noexcept
constexpr vector & operator= (const vector &__x)
Vector assignment operator.
constexpr vector & operator= (initializer_list< value_type > __l)
Vector list assignment operator.
constexpr vector & operator= (vector &&__x) noexcept(_Alloc_traits::_S_nothrow_move())
Vector move assignment operator.
constexpr const_reference operator[] (size_type __n) const noexcept
Subscript access to the data contained in the vector.
constexpr reference operator[] (size_type __n) noexcept
Subscript access to the data contained in the vector.
constexpr void pop_back () noexcept
Removes last element.
constexpr void push_back (const value_type &__x)
Add data to the end of the vector.
constexpr void push_back (value_type &&__x)
constexpr const_reverse_iterator rbegin () const noexcept
constexpr reverse_iterator rbegin () noexcept
constexpr const_reverse_iterator rend () const noexcept
constexpr reverse_iterator rend () noexcept
constexpr void reserve (size_type __n)
Attempt to preallocate enough memory for specified number of elements.
constexpr void resize (size_type __new_size)
Resizes the vector to the specified number of elements.
constexpr void resize (size_type __new_size, const value_type &__x)
Resizes the vector to the specified number of elements.
constexpr void shrink_to_fit ()
constexpr size_type size () const noexcept
constexpr void swap (vector &__x) noexcept
Swaps data with another vector.

constexpr pointer _M_allocate (size_t __n)
template<typename _ForwardIterator > constexpr pointer _M_allocate_and_copy (size_type __n, _ForwardIterator __first, _ForwardIterator __last)
template<typename _ForwardIterator > constexpr void _M_assign_aux (_ForwardIterator __first, _ForwardIterator __last, std::forward_iterator_tag)
template<typename _InputIterator > constexpr void _M_assign_aux (_InputIterator __first, _InputIterator __last, std::input_iterator_tag)
template<typename _InputIterator > constexpr void _M_assign_dispatch (_InputIterator __first, _InputIterator __last, __false_type)
template<typename _Integer > constexpr void _M_assign_dispatch (_Integer __n, _Integer __val, __true_type)
constexpr size_type _M_check_len (size_type __n, const char *__s) const
constexpr void _M_create_storage (size_t __n)
constexpr void _M_deallocate (pointer __p, size_t __n)
constexpr void _M_default_append (size_type __n)
constexpr void _M_default_initialize (size_type __n)
template<typename... _Args> constexpr iterator _M_emplace_aux (const_iterator __position, _Args &&... __args)
constexpr iterator _M_emplace_aux (const_iterator __position, value_type &&__v)
constexpr iterator _M_erase (iterator __first, iterator __last)
constexpr iterator _M_erase (iterator __position)
constexpr void _M_erase_at_end (pointer __pos) noexcept
constexpr void _M_fill_assign (size_type __n, const value_type &__val)
constexpr void _M_fill_initialize (size_type __n, const value_type &__value)
constexpr void _M_fill_insert (iterator __pos, size_type __n, const value_type &__x)
constexpr const _Tp_alloc_type & _M_get_Tp_allocator () const noexcept
constexpr _Tp_alloc_type & _M_get_Tp_allocator () noexcept
template<typename _Arg > constexpr void _M_insert_aux (iterator __position, _Arg &&__arg)
template<typename _InputIterator > constexpr void _M_insert_dispatch (iterator __pos, _InputIterator __first, _InputIterator __last, __false_type)
template<typename _Integer > constexpr void _M_insert_dispatch (iterator __pos, _Integer __n, _Integer __val, __true_type)
constexpr iterator _M_insert_rval (const_iterator __position, value_type &&__v)
constexpr void _M_range_check (size_type __n) const
Safety check used only from at().
template<typename _ForwardIterator > constexpr void _M_range_initialize (_ForwardIterator __first, _ForwardIterator __last, std::forward_iterator_tag)
template<typename _InputIterator > constexpr void _M_range_initialize (_InputIterator __first, _InputIterator __last, std::input_iterator_tag)
template<typename _ForwardIterator > constexpr void _M_range_insert (iterator __pos, _ForwardIterator __first, _ForwardIterator __last, std::forward_iterator_tag)
template<typename _InputIterator > constexpr void _M_range_insert (iterator __pos, _InputIterator __first, _InputIterator __last, std::input_iterator_tag)
template<typename... _Args> constexpr void _M_realloc_append (_Args &&... __args)
template<typename... _Args> constexpr void _M_realloc_insert (iterator __position, _Args &&... __args)
constexpr bool _M_shrink_to_fit ()

static constexpr size_type _S_check_init_len (size_type __n, const allocator_type &__a)
static constexpr size_type _S_max_size (const _Tp_alloc_type &__a) noexcept

_Vector_impl _M_impl

class std::vector< _Tp, _Alloc >"A standard container which offers fixed time access to individual elements in any order.

Since

C++98

Template Parameters

Meets the requirements of a container, a reversible container, and a sequence, including the optional sequence requirements with the exception of push_front and pop_front.

In some terminology a vector can be described as a dynamic C-style array, it offers fast and efficient access to individual elements in any order and saves the user from worrying about memory and size allocation. Subscripting ( [] ) access is also provided as with C-style arrays.

Creates a vector with no elements.

Creates a vector with no elements.

Parameters

Creates a vector with default constructed elements.

Parameters

This constructor fills the vector with __n default constructed elements.

Creates a vector with copies of an exemplar element.

Parameters

This constructor fills the vector with __n copies of __value.

Vector copy constructor.

Parameters

All the elements of __x are copied, but any unused capacity in __x will not be copied (i.e. capacity() == size() in the new vector).

The newly-created vector uses a copy of the allocator object used by __x (unless the allocator traits dictate a different object).

References std::vector< _Tp, _Alloc >::begin(), and std::vector< _Tp, _Alloc >::end().

Vector move constructor. The newly-created vector contains the exact contents of the moved instance. The contents of the moved instance are a valid, but unspecified vector.

Copy constructor with alternative allocator.

Move constructor with alternative allocator.

Builds a vector from an initializer list.

Parameters

Create a vector consisting of copies of the elements in the initializer_list __l.

This will call the element type's copy constructor N times (where N is __l.size()) and do no memory reallocation.

Builds a vector from a range.

Parameters

Create a vector consisting of copies of the elements from [first,last).

If the iterators are forward, bidirectional, or random-access, then this will call the elements' copy constructor N times (where N is distance(first,last)) and do no memory reallocation. But if only input iterators are used, then this will do at most 2N calls to the copy constructor, and logN memory reallocations.

References std::__iterator_category().

The dtor only erases the elements, and note that if the elements themselves are pointers, the pointed-to memory is not touched in any way. Managing the pointer is the user's responsibility.

References std::_Destroy().

Memory expansion handler. Uses the member allocation function to obtain n bytes of memory, and then copies [first,last) into it.

Safety check used only from at().

References std::vector< _Tp, _Alloc >::size().

Referenced by std::vector< _Tp, _Alloc >::at(), and std::vector< _Tp, _Alloc >::at().

Assigns a range to a vector.

Parameters

This function fills a vector with copies of the elements in the range [__first,__last).

Note that the assignment completely changes the vector and that the resulting vector's size is the same as the number of elements assigned.

References std::__iterator_category().

Assigns an initializer list to a vector.

Parameters

This function fills a vector with copies of the elements in the initializer list __l.

Note that the assignment completely changes the vector and that the resulting vector's size is the same as the number of elements assigned.

Assigns a given value to a vector.

Parameters

This function fills a vector with __n copies of the given value. Note that the assignment completely changes the vector and that the resulting vector's size is the same as the number of elements assigned.

Provides access to the data contained in the vector.

Parameters

Returns

Read/write reference to data.

Exceptions

std::out_of_range If __n is an invalid index.

This function provides for safer data access. The parameter is first checked that it is in the range of the vector. The function throws out_of_range if the check fails.

References std::vector< _Tp, _Alloc >::_M_range_check().

Provides access to the data contained in the vector.

Parameters

Returns

Read-only (constant) reference to data.

Exceptions

std::out_of_range If __n is an invalid index.

This function provides for safer data access. The parameter is first checked that it is in the range of the vector. The function throws out_of_range if the check fails.

References std::vector< _Tp, _Alloc >::_M_range_check().

Returns a read-only (constant) reference to the data at the last element of the vector.

References std::vector< _Tp, _Alloc >::end().

Returns a read/write reference to the data at the last element of the vector.

References std::vector< _Tp, _Alloc >::end().

Referenced by std::piecewise_constant_distribution< _RealType >::max(), and std::piecewise_linear_distribution< _RealType >::max().

Returns a read-only (constant) iterator that points to the first element in the vector. Iteration is done in ordinary element order.

Returns a read/write iterator that points to the first element in the vector. Iteration is done in ordinary element order.

Referenced by std::vector< _Tp, _Alloc >::vector(), std::match_results< _Bi_iter, _Alloc >::begin(), std::vector< _Tp, _Alloc >::crend(), std::vector< _Tp, _Alloc >::empty(), std::vector< _Tp, _Alloc >::erase(), std::vector< _Tp, _Alloc >::erase(), std::vector< _Tp, _Alloc >::front(), std::vector< _Tp, _Alloc >::front(), std::vector< _Tp, _Alloc >::insert(), std::vector< _Tp, _Alloc >::insert(), std::vector< _Tp, _Alloc >::insert(), __gnu_parallel::multiway_merge_exact_splitting(), std::operator<=>(), std::operator==(), std::vector< _Tp, _Alloc >::rend(), and std::vector< _Tp, _Alloc >::rend().

Returns the total number of elements that the vector can hold before needing to allocate more memory.

Returns a read-only (constant) iterator that points to the first element in the vector. Iteration is done in ordinary element order.

Referenced by std::vector< _Tp, _Alloc >::erase(), std::vector< _Tp, _Alloc >::erase(), std::vector< _Tp, _Alloc >::insert(), std::vector< _Tp, _Alloc >::insert(), and std::vector< _Tp, _Alloc >::insert().

Returns a read-only (constant) iterator that points one past the last element in the vector. Iteration is done in ordinary element order.

Erases all the elements. Note that this function only erases the elements, and that if the elements themselves are pointers, the pointed-to memory is not touched in any way. Managing the pointer is the user's responsibility.

Returns a read-only (constant) reverse iterator that points to the last element in the vector. Iteration is done in reverse element order.

References std::vector< _Tp, _Alloc >::end().

Returns a read-only (constant) reverse iterator that points to one before the first element in the vector. Iteration is done in reverse element order.

References std::vector< _Tp, _Alloc >::begin().

Returns a pointer such that [data(), data() + size()) is a valid range. For a non-empty vector, data() == &front().

Inserts an object in vector before specified iterator.

Parameters

Returns

An iterator that points to the inserted data.

This function will insert an object of type T constructed with T(std::forward<Args>(args)...) before the specified location. Note that this kind of operation could be expensive for a vector and if it is frequently used the user should consider using std::list.

References std::forward().

Returns true if the vector is empty. (Thus begin() would equal end().)

References std::vector< _Tp, _Alloc >::begin(), and std::vector< _Tp, _Alloc >::end().

Referenced by std::piecewise_constant_distribution< _RealType >::densities(), std::piecewise_linear_distribution< _RealType >::densities(), std::match_results< _Bi_iter, _Alloc >::end(), std::piecewise_constant_distribution< _RealType >::intervals(), std::piecewise_linear_distribution< _RealType >::intervals(), std::discrete_distribution< _IntType >::max(), std::piecewise_constant_distribution< _RealType >::max(), std::piecewise_linear_distribution< _RealType >::max(), std::piecewise_constant_distribution< _RealType >::min(), std::piecewise_linear_distribution< _RealType >::min(), std::discrete_distribution< _IntType >::probabilities(), std::match_results< _Bi_iter, _Alloc >::ready(), and std::match_results< _Bi_iter, _Alloc >::size().

Returns a read-only (constant) iterator that points one past the last element in the vector. Iteration is done in ordinary element order.

Returns a read/write iterator that points one past the last element in the vector. Iteration is done in ordinary element order.

Referenced by std::vector< _Tp, _Alloc >::vector(), std::vector< _Tp, _Alloc >::back(), std::vector< _Tp, _Alloc >::back(), std::vector< _Tp, _Alloc >::crbegin(), std::vector< _Tp, _Alloc >::empty(), std::match_results< _Bi_iter, _Alloc >::end(), __gnu_parallel::multiway_merge_exact_splitting(), std::operator<=>(), std::operator==(), std::vector< _Tp, _Alloc >::rbegin(), std::vector< _Tp, _Alloc >::rbegin(), and std::vector< _Tp, _Alloc >::resize().

Remove a range of elements.

Parameters

Returns

An iterator pointing to the element pointed to by __last prior to erasing (or end()).

This function will erase the elements in the range [__first,__last) and shorten the vector accordingly.

Note This operation could be expensive and if it is frequently used the user should consider using std::list. The user is also cautioned that this function only erases the elements, and that if the elements themselves are pointers, the pointed-to memory is not touched in any way. Managing the pointer is the user's responsibility.

References std::vector< _Tp, _Alloc >::begin(), and std::vector< _Tp, _Alloc >::cbegin().

Remove element at given position.

Parameters

Returns

An iterator pointing to the next element (or end()).

This function will erase the element at the given position and thus shorten the vector by one.

Note This operation could be expensive and if it is frequently used the user should consider using std::list. The user is also cautioned that this function only erases the element, and that if the element is itself a pointer, the pointed-to memory is not touched in any way. Managing the pointer is the user's responsibility.

References std::vector< _Tp, _Alloc >::begin(), and std::vector< _Tp, _Alloc >::cbegin().

Returns a read-only (constant) reference to the data at the first element of the vector.

References std::vector< _Tp, _Alloc >::begin().

Returns a read/write reference to the data at the first element of the vector.

References std::vector< _Tp, _Alloc >::begin().

Referenced by std::piecewise_constant_distribution< _RealType >::min(), and std::piecewise_linear_distribution< _RealType >::min().

Get a copy of the memory allocation object.

Referenced by std::match_results< _Bi_iter, _Alloc >::get_allocator().

Inserts a range into the vector.

Parameters

Returns

An iterator that points to the inserted data.

This function will insert copies of the data in the range [__first,__last) into the vector before the location specified by pos.

Note that this kind of operation could be expensive for a vector and if it is frequently used the user should consider using std::list.

References std::__iterator_category(), std::vector< _Tp, _Alloc >::begin(), and std::vector< _Tp, _Alloc >::cbegin().

Inserts given value into vector before specified iterator.

Parameters

Returns

An iterator that points to the inserted data.

This function will insert a copy of the given value before the specified location. Note that this kind of operation could be expensive for a vector and if it is frequently used the user should consider using std::list.

References std::begin(), std::cbegin(), std::end(), and std::move().

Inserts an initializer_list into the vector.

Parameters

This function will insert copies of the data in the initializer_list l into the vector before the location specified by position.

Note that this kind of operation could be expensive for a vector and if it is frequently used the user should consider using std::list.

References std::vector< _Tp, _Alloc >::begin(), and std::vector< _Tp, _Alloc >::cbegin().

Inserts a number of copies of given data into the vector.

Parameters

Returns

An iterator that points to the inserted data.

This function will insert a specified number of copies of the given data before the location specified by position.

Note that this kind of operation could be expensive for a vector and if it is frequently used the user should consider using std::list.

References std::vector< _Tp, _Alloc >::begin(), and std::vector< _Tp, _Alloc >::cbegin().

Inserts given rvalue into vector before specified iterator.

Parameters

Returns

An iterator that points to the inserted data.

This function will insert a copy of the given rvalue before the specified location. Note that this kind of operation could be expensive for a vector and if it is frequently used the user should consider using std::list.

References std::move().

Returns the size() of the largest possible vector.

Referenced by std::match_results< _Bi_iter, _Alloc >::max_size().

Vector assignment operator.

Parameters

All the elements of __x are copied, but any unused capacity in __x will not be copied.

Whether the allocator is copied depends on the allocator traits.

Vector list assignment operator.

Parameters

This function fills a vector with copies of the elements in the initializer list __l.

Note that the assignment completely changes the vector and that the resulting vector's size is the same as the number of elements assigned.

Vector move assignment operator.

Parameters

The contents of __x are moved into this vector (without copying, if the allocators permit it). Afterwards __x is a valid, but unspecified vector.

Whether the allocator is moved depends on the allocator traits.

References std::move().

Subscript access to the data contained in the vector.

Parameters

Returns

Read-only (constant) reference to data.

This operator allows for easy, array-style, data access. Note that data access with this operator is unchecked and out_of_range lookups are not defined. (For checked lookups see at().)

Subscript access to the data contained in the vector.

Parameters

Returns

Read/write reference to data.

This operator allows for easy, array-style, data access. Note that data access with this operator is unchecked and out_of_range lookups are not defined. (For checked lookups see at().)

Referenced by std::match_results< _Bi_iter, _Alloc >::operator[]().

Removes last element. This is a typical stack operation. It shrinks the vector by one.

Note that no data is returned, and if the last element's data is needed, it should be retrieved before pop_back() is called.

Add data to the end of the vector.

Parameters

This is a typical stack operation. The function creates an element at the end of the vector and assigns the given data to it. Due to the nature of a vector this operation can be done in constant time if the vector has preallocated space available.

Returns a read-only (constant) reverse iterator that points to the last element in the vector. Iteration is done in reverse element order.

References std::vector< _Tp, _Alloc >::end().

Returns a read/write reverse iterator that points to the last element in the vector. Iteration is done in reverse element order.

References std::vector< _Tp, _Alloc >::end().

Returns a read-only (constant) reverse iterator that points to one before the first element in the vector. Iteration is done in reverse element order.

References std::vector< _Tp, _Alloc >::begin().

Returns a read/write reverse iterator that points to one before the first element in the vector. Iteration is done in reverse element order.

References std::vector< _Tp, _Alloc >::begin().

Attempt to preallocate enough memory for specified number of elements.

Parameters

Exceptions

std::length_error If n exceeds max_size().

This function attempts to reserve enough memory for the vector to hold the specified number of elements. If the number requested is more than max_size(), length_error is thrown.

The advantage of this function is that if optimal code is a necessity and the user can determine the number of elements that will be required, the user can reserve the memory in advance, and thus prevent a possible reallocation of memory and copying of vector data.

References std::_Destroy(), and std::size().

Resizes the vector to the specified number of elements.

Parameters

This function will resize the vector to the specified number of elements. If the number is smaller than the vector's current size the vector is truncated, otherwise default constructed elements are appended.

References std::vector< _Tp, _Alloc >::size().

Referenced by __gnu_parallel::__shrink_and_double(), and __gnu_parallel::multiway_merge_exact_splitting().

Resizes the vector to the specified number of elements.

Parameters

This function will resize the vector to the specified number of elements. If the number is smaller than the vector's current size the vector is truncated, otherwise the vector is extended and new elements are populated with given data.

References std::vector< _Tp, _Alloc >::end(), and std::vector< _Tp, _Alloc >::size().

A non-binding request to reduce capacity() to size().

Returns the number of elements in the vector.

Referenced by __gnu_parallel::__shrink(), __gnu_parallel::__shrink_and_double(), std::vector< _Tp, _Alloc >::_M_range_check(), std::match_results< _Bi_iter, _Alloc >::empty(), __gnu_parallel::list_partition(), std::discrete_distribution< _IntType >::max(), std::operator==(), std::vector< _Tp, _Alloc >::resize(), std::vector< _Tp, _Alloc >::resize(), and std::match_results< _Bi_iter, _Alloc >::size().

Swaps data with another vector.

Parameters

This exchanges the elements between two vectors in constant time. (Three pointers, so it should be quite fast.) Note that the global std::swap() function is specialized such that std::swap(v1,v2) will feed to this function.

Whether the allocators are swapped depends on the allocator traits.

Referenced by std::match_results< _Bi_iter, _Alloc >::swap().