<vector>

Include the STL standard header <vector> to define the container template class vector and several supporting templates.

namespace std {
template<class Ty, class Alloc>
    class vector;
template<class Alloc>
    class vector<bool>;

        // TEMPLATE FUNCTIONS
template<class Ty, class Alloc>
    bool operator==(
        const vector<Ty, Alloc>& left,
        const vector<Ty, Alloc>& right);
template<class Ty, class Alloc>
    bool operator!=(
        const vector<Ty, Alloc>& left,
        const vector<Ty, Alloc>& right);
template<class Ty, class Alloc>
    bool operator<(
        const vector<Ty, Alloc>& left,
        const vector<Ty, Alloc>& right);
template<class Ty, class Alloc>
    bool operator>(
        const vector<Ty, Alloc>& left,
        const vector<Ty, Alloc>& right);
template<class Ty, class Alloc>
    bool operator<=(
        const vector<Ty, Alloc>& left,
        const vector<Ty, Alloc>& right);
template<class Ty, class Alloc>
    bool operator>=(
        const vector<Ty, Alloc>& left,
        const vector<Ty, Alloc>& right);
template<class Ty, class Alloc>
    void swap(
        vector<Ty, Alloc>& left,
        vector<Ty, Alloc>& right);
    };

operator!=

template<class Ty, class Alloc>
    bool operator!=(
        const vector <Ty, Alloc>& left,
        const vector <Ty, Alloc>& right);

The template function returns !(left == right).

operator==

template<class Ty, class Alloc>
    bool operator==(
        const vector <Ty, Alloc>& left,
        const vector <Ty, Alloc>& right);

The template function overloads operator== to compare two objects of template class vector. The function returns left.size() == right.size() && equal(left. begin(), left. end(), right.begin()).

operator<

template<class Ty, class Alloc>
    bool operator<(
        const vector <Ty, Alloc>& left,
        const vector <Ty, Alloc>& right);

The template function overloads operator< to compare two objects of template class vector. The function returns lexicographical_compare(left. begin(), left. end(), right.begin(), right.end()).

operator<=

template<class Ty, class Alloc>
    bool operator<=(
        const vector <Ty, Alloc>& left,
        const vector <Ty, Alloc>& right);

The template function returns !(right < left).

operator>

template<class Ty, class Alloc>
    bool operator>(
        const vector <Ty, Alloc>& left,
        const vector <Ty, Alloc>& right);

The template function returns right < left.

operator>=

template<class Ty, class Alloc>
    bool operator>=(
        const vector <Ty, Alloc>& left,
        const vector <Ty, Alloc>& right);

The template function returns !(left < right).

swap

template<class Ty, class Alloc>
    void swap(
        vector <Ty, Alloc>& left,
        vector <Ty, Alloc>& right);

The template function executes left.swap(right).

vector

allocator_type · assign · at · back · begin · capacity · clear · const_iterator · const_pointer · const_reference · const_reverse_iterator · difference_type · empty · end · erase · front · get_allocator · insert · iterator · max_size · operator[] · pointer · pop_back · push_back · rbegin · reference · rend · reserve · resize · reverse_iterator · size · size_type · swap · value_type · vector

template<class Ty, class Alloc = allocator<Ty> >
    class vector {
public:
    typedef Alloc allocator_type;
    typedef typename Alloc::pointer pointer;
    typedef typename Alloc::const_pointer
        const_pointer;
    typedef typename Alloc::reference reference;
    typedef typename Alloc::const_reference
        const_reference;
    typedef typename Alloc::value_type value_type;
    typedef T0 iterator;
    typedef T1 const_iterator;
    typedef T2 size_type;
    typedef T3 difference_type;
    typedef reverse_iterator<const_iterator>
        const_reverse_iterator;
    typedef reverse_iterator<iterator>
        reverse_iterator;
    vector();
    explicit vector(const Alloc& al);
    explicit vector(size_type count);
    vector(size_type count, const Ty& val);
    vector(size_type count, const Ty& val,
        const Alloc& al);
    vector(const vector& right);
    template<class InIt>
        vector(InIt first, InIt last);
    template<class InIt>
        vector(InIt first, InIt last,
            const Alloc& al);
    void reserve(size_type count);
    size_type capacity() const;
    iterator begin();
    const_iterator begin() const;
    iterator end();
    const_iterator end() const;
    reverse_iterator rbegin();
    const_reverse_iterator rbegin() const;
    reverse_iterator rend();
    const_reverse_iterator rend() const;
    void resize(size_type newsize);
    void resize(size_type newsize, Ty val);
    size_type size() const;
    size_type max_size() const;
    bool empty() const;
    Alloc get_allocator() const;
    reference at(size_type off);
    const_reference at(size_type off) const;
    reference operator[](size_type off);
    const_reference operator[](size_type off);
    reference front();
    const_reference front() const;
    reference back();
    const_reference back() const;
    void push_back(const Ty& val);
    void pop_back();
    template<class InIt>
        void assign(InIt first, InIt last);
    void assign(size_type count, const Ty& val);
    iterator insert(iterator where, const Ty& val);
    void insert(iterator where, size_type count, const Ty& val);
    template<class InIt>
        void insert(iterator where, InIt first, InIt last);
    iterator erase(iterator where);
    iterator erase(iterator first, iterator last);
    void clear();
    void swap(vector& right);
    };

The template class describes an object that controls a varying-length sequence of elements of type Ty. The sequence is stored as an array of Ty.

The object allocates and frees storage for the sequence it controls through a stored allocator object of class Alloc. Such an allocator object must have the same external interface as an object of template class allocator. Note that the stored allocator object is not copied when the container object is assigned.

Vector reallocation occurs when a member function must grow the controlled sequence beyond its current storage capacity. Other insertions and erasures may alter various storage addresses within the sequence. In all such cases, iterators or references that point at altered portions of the controlled sequence become invalid.

vector::allocator_type

typedef Alloc allocator_type;

The type is a synonym for the template parameter Alloc.

vector::assign

template<class InIt>
    void assign(InIt first, InIt last);
void assign(size_type count, const Ty& val);

If InIt is an integer type, the first member function behaves the same as assign((size_type)first, (Ty)last). Otherwise, the first member function replaces the sequence controlled by *this with the sequence [first, last), which must not overlap the initial controlled sequence. The second member function replaces the sequence controlled by *this with a repetition of count elements of value val.

vector::at

const_reference at(size_type off) const;
reference at(size_type off);

The member function returns a reference to the element of the controlled sequence at position off. If that position is invalid, the function throws an object of class out_of_range.

vector::back

reference back();
const_reference back() const;

The member function returns a reference to the last element of the controlled sequence, which must be non-empty.

vector::begin

const_iterator begin() const;
iterator begin();

The member function returns a random-access iterator that points at the first element of the sequence (or just beyond the end of an empty sequence).

vector::capacity

size_type capacity() const;

The member function returns the storage currently allocated to hold the controlled sequence, a value at least as large as size().

vector::clear

void clear();

The member function calls erase( begin(), end()).

vector::const_iterator

typedef T1 const_iterator;

The type describes an object that can serve as a constant random-access iterator for the controlled sequence. It is described here as a synonym for the implementation-defined type T1.

vector::const_pointer

typedef typename Alloc::const_pointer
    const_pointer;

The type describes an object that can serve as a constant pointer to an element of the controlled sequence.

vector::const_reference

typedef typename Alloc::const_reference
    const_reference;

The type describes an object that can serve as a constant reference to an element of the controlled sequence.

vector::const_reverse_iterator

typedef reverse_iterator<const_iterator>
    const_reverse_iterator;

The type describes an object that can serve as a constant reverse iterator for the controlled sequence.

vector::difference_type

typedef T3 difference_type;

The signed integer type describes an object that can represent the difference between the addresses of any two elements in the controlled sequence. It is described here as a synonym for the implementation-defined type T3.

vector::empty

bool empty() const;

The member function returns true for an empty controlled sequence.

vector::end

const_iterator end() const;
iterator end();

The member function returns a random-access iterator that points just beyond the end of the sequence.

vector::erase

iterator erase(iterator where);
iterator erase(iterator first, iterator last);

The first member function removes the element of the controlled sequence pointed to by where. The second member function removes the elements of the controlled sequence in the range [first, last). Both return an iterator that designates the first element remaining beyond any elements removed, or end() if no such element exists.

Erasing N elements causes N destructor calls and an assignment for each of the elements between the insertion point and the end of the sequence. No reallocation occurs, so iterators and references become invalid only from the first element erased through the end of the sequence.

The member functions throw an exception only if a copy operation throws an exception.

vector::front

reference front();
const_reference front() const;

The member function returns a reference to the first element of the controlled sequence, which must be non-empty.

vector::get_allocator

Alloc get_allocator() const;

The member function returns the stored allocator object.

vector::insert

iterator insert(iterator where, const Ty& val);
void insert(iterator where, size_type count, const Ty& val);
template<class InIt>
    void insert(iterator where, InIt first, InIt last);

Each of the member functions inserts, before the element pointed to by where in the controlled sequence, a sequence specified by the remaining operands. The first member function inserts a single element with value val and returns an iterator that designates the newly inserted element. The second member function inserts a repetition of count elements of value val.

If InIt is an integer type, the last member function behaves the same as insert(where, (size_type)first, (Ty)last). Otherwise, the last member function inserts the sequence [first, last), which must not overlap the initial controlled sequence.

When inserting a single element, the number of element copies is linear in the number of elements between the insertion point and the end of the sequence. When inserting a single element at the end of the sequence, the amortized number of element copies is constant. When inserting N elements, the number of element copies is linear in N plus the number of elements between the insertion point and the end of the sequence -- except when the template member is specialized for InIt an input iterator, which behaves like N single insertions.

If reallocation occurs, the capacity increases by a fixed factor (at least), and all iterators and references become invalid. If no reallocation occurs, iterators become invalid only from the point of insertion through the end of the sequence.

If an exception is thrown during the insertion of one or more elements, and the exception is not thrown while copying an element, the container is left unaltered and the exception is rethrown.

vector::iterator

typedef T0 iterator;

The type describes an object that can serve as a random-access iterator for the controlled sequence. It is described here as a synonym for the implementation-defined type T0.

vector::max_size

size_type max_size() const;

The member function returns the length of the longest sequence that the object can control.

vector::operator[]

const_reference operator[](size_type off) const;
reference operator[](size_type off);

The member function returns a reference to the element of the controlled sequence at position off. If that position is invalid, the behavior is undefined.

vector::pointer

typedef typename Alloc::pointer pointer;

The type describes an object that can serve as a pointer to an element of the controlled sequence.

vector::pop_back

void pop_back();

The member function removes the last element of the controlled sequence, which must be non-empty.

The member function never throws an exception.

vector::push_back

void push_back(const Ty& val);

The member function inserts an element with value val at the end of the controlled sequence.

If an exception is thrown, the container is left unaltered and the exception is rethrown.

vector::rbegin

const_reverse_iterator rbegin() const;
reverse_iterator rbegin();

The member function returns a reverse iterator that points just beyond the end of the controlled sequence. Hence, it designates the beginning of the reverse sequence.

vector::reference

typedef typename Alloc::reference reference;

The type describes an object that can serve as a reference to an element of the controlled sequence.

vector::rend

const_reverse_iterator rend() const;
reverse_iterator rend();

The member function returns a reverse iterator that points at the first element of the sequence (or just beyond the end of an empty sequence). Hence, it designates the end of the reverse sequence.

vector::reserve

void reserve(size_type count);

If count is greater than max_size(), the member function reports a length error by throwing an object of class length_error. Otherwise, it ensures that capacity() henceforth returns at least count.

vector::resize

void resize(size_type newsize);
void resize(size_type newsize, Ty val);

The member functions both ensure that size() henceforth returns newsize. If it must make the controlled sequence longer, the first member function appends elements with value Ty(), while the second member function appends elements with value val. To make the controlled sequence shorter, both member functions call erase(begin() + newsize, end()).

vector::reverse_iterator

typedef reverse_iterator<iterator>
    reverse_iterator;

The type describes an object that can serve as a reverse iterator for the controlled sequence.

vector::size

size_type size() const;

The member function returns the length of the controlled sequence.

vector::size_type

typedef T2 size_type;

The unsigned integer type describes an object that can represent the length of any controlled sequence. It is described here as a synonym for the implementation-defined type T2.

vector::swap

void swap(vector& right);

The member function swaps the controlled sequences between *this and right. If get_allocator() == right.get_allocator(), it does so in constant time, it throws no exceptions, and it invalidates no references, pointers, or iterators that designate elements in the two controlled sequences. Otherwise, it performs a number of element assignments and constructor calls proportional to the number of elements in the two controlled sequences.

vector::value_type

typedef typename Alloc::value_type value_type;

The type is a synonym for the template parameter Ty.

vector::vector

vector();
explicit vector(const Alloc& al);
explicit vector(size_type count);
vector(size_type count, const Ty& val);
vector(size_type count, const Ty& val, const Alloc& al);
vector(const vector& right);
template<class InIt>
    vector(InIt first, InIt last);
template<class InIt>
    vector(InIt first, InIt last, const Alloc& al);

All constructors store an allocator object and initialize the controlled sequence. The allocator object is the argument al, if present. For the copy constructor, it is right.get_allocator(). Otherwise, it is Alloc().

The first two constructors specify an empty initial controlled sequence. The third constructor specifies a repetition of count elements of value Ty(). The fourth and fifth constructors specify a repetition of count elements of value val. The sixth constructor specifies a copy of the sequence controlled by right. If InIt is an integer type, the last two constructors specify a repetition of (size_type)first elements of value (Ty)last. Otherwise, the last two constructors specify the sequence [first, last).

vector<bool, Alloc>

template<class Alloc>
    class vector<bool, Alloc> {
public:
    class reference;
    typedef bool const_reference;
    typedef T0 iterator;
    typedef T1 const_iterator;
    typedef T4 pointer;
    typedef T5 const_pointer;
    void flip();
    static void swap(reference left, reference right);
// rest same as template class vector
    };

The class is a partial specialization of template class vector for elements of type bool. It alters the definition of four member types (to optimize the packing and unpacking of elements) and adds two member functions. Its behavior is otherwise the same as for template class vector.

vector<bool, Alloc>::const_iterator

typedef T1 const_iterator;

The type describes an object that can serve as a constant random-access iterator for the controlled sequence. It is described here as a synonym for the unspecified type T1.

vector<bool, Alloc>::const_pointer

typedef T5 const_pointer;

The type describes an object that can serve as a pointer to a constant element of the controlled sequence. It is described here as a synonym for the unspecified type T5.

vector<bool, Alloc>::const_reference

typedef bool const_reference;

The type describes an object that can serve as a constant reference to an element of the controlled sequence, in this case bool.

vector<bool, Alloc>::flip

void flip();

The member function inverts the values of all the members of the controlled sequence.

vector<bool, Alloc>::iterator

typedef T0 iterator;

The type describes an object that can serve as a random-access iterator for the controlled sequence. It is described here as a synonym for the unspecified type T0.

vector<bool, Alloc>::pointer

typedef T4 pointer;

The type describes an object that can serve as a pointer to an element of the controlled sequence. It is described here as a synonym for the unspecified type T4.

vector<bool, Alloc>::reference

class reference {
public:
    reference& operator=(const reference& right);
    reference& operator=(bool val);
    void flip();
    bool operator~() const;
    operator bool() const;
    };

The type describes an object that can serve as a reference to an element of the controlled sequence. Specifically, for two objects ref and ref2 of class reference:

• bool(ref) yields the value of the element designated by ref
• ~ref yields the inverted value of the element designated by ref
• ref.flip() inverts the value designated by ref
• ref2 = bool(ref) and ref2 = ref both assign the value of the element designated by ref to the element designated by ref2

It is unspecified how member functions of class vector<bool> construct objects of class reference that designate elements of a controlled sequence. The default constructor for class reference generates an object that refers to no such element.

vector<bool, Alloc>::swap

void swap(reference left, reference right);

The static member function swaps the members of the controlled sequences designated by left and right.

See also the Table of Contents and the Index.

Copyright © 1994-2002 by P.J. Plauger. Portions derived from work copyright © 1994 by Hewlett-Packard Company. All rights reserved.