deque(C++std)

operator== , operator!= , operator< , operator> , operator<= , operator>= , swap - defines a template class that implements a deque container (standard template library)

Synopsis

   namespace std {
   template<class T, class A>
       class deque;

           // TEMPLATE FUNCTIONS
   template<class T, class A>
       bool operator==(
           const deque<T, A>& lhs,
           const deque<T, A>& rhs);
   template<class T, class A>
       bool operator!=(
           const deque<T, A>& lhs,
           const deque<T, A>& rhs);
   template<class T, class A>
       bool operator<(
           const deque<T, A>& lhs,
           const deque<T, A>& rhs);
   template<class T, class A>
       bool operator>(
           const deque<T, A>& lhs,
           const deque<T, A>& rhs);
   template<class T, class A>
       bool operator<=(
           const deque<T, A>& lhs,
           const deque<T, A>& rhs);
   template<class T, class A>
       bool operator>=(
           const deque<T, A>& lhs,
           const deque<T, A>& rhs);
   template<class T, class A>
       void swap(
           deque<T, A>& lhs,
           deque<T, A>& rhs);
       };

Description

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

`deque`

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

   template<class T, class A = allocator<T> >
       class deque {
   public:
       typedef A allocator_type;
       typedef typename A::pointer pointer;
       typedef typename A::const_pointer const_pointer;
       typedef typename A::reference reference;
       typedef typename A::const_reference const_reference;
       typedef typename A::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;
       deque();
       explicit deque(const A& al);
       explicit deque(size_type n);
       deque(size_type n, const T& v);
       deque(size_type n, const T& v,
           const A& al);
       deque(const deque& x);
       template<class InIt>
           deque(InIt first, InIt last);
       template<class InIt>
           deque(InIt first, InIt last, const A& al);
       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 n);
       void resize(size_type n, T x);
       size_type size() const;
       size_type max_size() const;
       bool empty() const;
       A get_allocator() const;
       reference at(size_type pos);
       const_reference at(size_type pos) const;
       reference operator[](size_type pos);
       const_reference operator[](size_type pos);
       reference front();
       const_reference front() const;
       reference back();
       const_reference back() const;
       void push_front(const T& x);
       void pop_front();
       void push_back(const T& x);
       void pop_back();
       template<class InIt>
           void assign(InIt first, InIt last);
       void assign(size_type n, const T& x);
       iterator insert(iterator it, const T& x);
       void insert(iterator it, size_type n, const T& x);
       template<class InIt>
           void insert(iterator it, InIt first, InIt last);
       iterator erase(iterator it);
       iterator erase(iterator first, iterator last);
       void clear();
       void swap(deque& x);
       };

The template class describes an object that controls a varying-length sequence of elements of type T. The sequence is represented in a way that permits insertion and removal of an element at either end with a single element copy (constant time). Such operations in the middle of the sequence require element copies and assignments proportional to the number of elements in the sequence (linear time).

The object allocates and frees storage for the sequence it controls through a stored allocator object of class A. 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.

Deque reallocation occurs when a member function must insert or erase elements of the controlled sequence:

If an element is inserted into an empty sequence, or if an element is erased to leave an empty sequence, then iterators earlier returned by begin() and end() become invalid.
If an element is inserted at begin() or at end(), then all iterators become invalid, but no references that designate existing elements become invalid.
If an element is erased at begin() or at end(), then only iterators and references that designate the erased element become invalid.
Otherwise, inserting or erasing an element invalidates all iterators and references.

deque::allocator_type

   typedef A allocator_type;

The type is a synonym for the template parameter A.

deque::assign

   template<class InIt>
       void assign(InIt first, InIt last);
   void assign(size_type n, const T& x);

If InIt is an integer type, the first member function behaves the same as assign((size_type)first, (T)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 n elements of value x.

deque::at

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

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

deque::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.

deque::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).

deque::clear

   void clear();

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

deque::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.

deque::const_pointer

   typedef typename A::const_pointer const_pointer;

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

deque::const_reference

   typedef typename A::const_reference const_reference;

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

deque::const_reverse_iterator

   typedef reverse_iterator<const_iterator>
       const_reverse_iterator;

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

deque::deque

   deque();
   explicit deque(const A& al);
   explicit deque(size_type n);
   deque(size_type n, const T& v);
   deque(size_type n, const T& v,
       const A& al);
   deque(const deque& x);
   template<class InIt>
       deque(InIt first, InIt last);
   template<class InIt>
       deque(InIt first, InIt last, const A& 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 x.get_allocator(). Otherwise, it is A().

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

deque::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.

deque::empty

   bool empty() const;

The member function returns true for an empty controlled sequence.

deque::end

   const_iterator end() const;
   iterator end();

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

deque::erase

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

The first member function removes the element of the controlled sequence pointed to by it. 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.

Removing N elements causes N destructor calls and an assignment for each of the elements between the insertion point and the nearer end of the sequence. Removing an element at either end invalidates only iterators and references that designate the erased elements. Otherwise, erasing an element invalidates all iterators and references.

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

deque::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.

deque::get_allocator

   A get_allocator() const;

The member function returns the stored allocator object.

deque::insert

   iterator insert(iterator it, const T& x);
   void insert(iterator it, size_type n, const T& x);
   template<class InIt>
       void insert(iterator it, InIt first, InIt last);

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

If InIt is an integer type, the last member function behaves the same as insert(it, (size_type)first, (T)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 nearer end of the sequence. When inserting a single element at either 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 nearer end of the sequence -- except when the template member is specialized for InIt an input or forward iterator, which behaves like N single insertions. Inserting an element at either end invalidates all iterators, but no references, that designate existing elements. Otherwise, inserting an element invalidates all iterators and references.

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.

deque::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.

deque::max_size

   size_type max_size() const;

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

deque::operator[]

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

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

deque::pointer

   typedef typename A::pointer pointer;

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

deque::pop_back

   void pop_back();

The member function removes the last element of the controlled sequence, which must be non-empty. Removing the element invalidates only iterators and references that designate the erased element.

The member function never throws an exception.

deque::pop_front

   void pop_front();

The member function removes the first element of the controlled sequence, which must be non-empty. Removing the element invalidates only iterators and references that designate the erased element.

The member function never throws an exception.

deque::push_back

   void push_back(const T& x);

The member function inserts an element with value x at the end of the controlled sequence. Inserting the element invalidates all iterators, but no references, to existing elements.

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

deque::push_front

   void push_front(const T& x);

The member function inserts an element with value x at the beginning of the controlled sequence. Inserting the element invalidates all iterators, but no references, to existing elements.

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

deque::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.

deque::reference

   typedef typename A::reference reference;

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

deque::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.

deque::resize

   void resize(size_type n);
   void resize(size_type n, T x);

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

deque::reverse_iterator

   typedef reverse_iterator<iterator>
       reverse_iterator;

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

deque::size

   size_type size() const;

The member function returns the length of the controlled sequence.

deque::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.

deque::swap

   void swap(deque& x);

The member function swaps the controlled sequences between *this and x. If get_allocator() == x.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.

deque::value_type

   typedef typename A::value_type value_type;

The type is a synonym for the template parameter T.

`operator!=`

   template<class T, class A>
       bool operator!=(
           const deque <T, A>& lhs,
           const deque <T, A>& rhs);

The template function returns !(lhs == rhs).

`operator==`

   template<class T, class A>
       bool operator==(
           const deque <T, A>& lhs,
           const deque <T, A>& rhs);

The template function overloads operator== to compare two objects of template class deque. The function returns lhs.size() == rhs.size() && equal(lhs. begin(), lhs. end(), rhs.begin()).

`operator<`

   template<class T, class A>
       bool operator<(
           const deque <T, A>& lhs,
           const deque <T, A>& rhs);

The template function overloads operator< to compare two objects of template class deque. The function returns lexicographical_compare(lhs. begin(), lhs. end(), rhs.begin(), rhs.end()).

`operator<=`

   template<class T, class A>
       bool operator<=(
           const deque <T, A>& lhs,
           const deque <T, A>& rhs);

The template function returns !(rhs < lhs).

`operator>`

   template<class T, class A>
       bool operator>(
           const deque <T, A>& lhs,
           const deque <T, A>& rhs);

The template function returns rhs < lhs.

`operator>=`

   template<class T, class A>
       bool operator>=(
           const deque <T, A>& lhs,
           const deque <T, A>& rhs);

The template function returns !(lhs < rhs).

`swap`

   template<class T, class A>
       void swap(
           deque <T, A>& lhs,
           deque <T, A>& rhs);

The template function executes lhs.swap(rhs).

References

algorithm() , memory(C++std)