list(C++std)

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

Synopsis

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

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

Description

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

list

allocator_type , assign , back , begin , clear , const_iterator , const_pointer , const_reference , const_reverse_iterator , difference_type , empty , end , erase , front , get_allocator , insert , iterator , list , max_size , merge , pointer , pop_back , pop_front , push_back , push_front , rbegin , reference , remove , remove_if , rend , resize , reverse , reverse_iterator , size , size_type , sort , splice , swap , unique , value_type

   template<class T, class A = allocator<T> >
       class list {
   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;
       list();
       explicit list(const A& al);
       explicit list(size_type n);
       list(size_type n, const T& v);
       list(size_type n, const T& v, const A& al);
       list(const list& x);
       template<class InIt>
           list(InIt first, InIt last);
       template<class InIt>
           list(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 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(list& x);
       void splice(iterator it, list& x);
       void splice(iterator it, list& x, iterator first);
       void splice(iterator it, list& x, iterator first,
           iterator last);
       void remove(const T& x);
       templace<class Pred>
           void remove_if(Pred pr);
       void unique();
       template<class Pred>
           void unique(Pred pr);
       void merge(list& x);
       template<class Pred>
           void merge(list& x, Pred pr);
       void sort();
       template<class Pred>
           void sort(Pred pr);
       void reverse();
       };

The template class describes an object that controls a varying-length sequence of elements of type T. The sequence is stored as a bidirectional linked list of elements, each containing a member of type T.

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.

List reallocation occurs when a member function must insert or erase elements of the controlled sequence. In all such cases, only iterators or references that point at erased portions of the controlled sequence become invalid.

All additions to the controlled sequence occur as if by calls to insert, which is the only member function that calls the constructor T(const T&). If such an expression throws an exception, the container object inserts no new elements and rethrows the exception. Thus, an object of template class list is left in a known state when such exceptions occur.

list::allocator_type

   typedef A allocator_type;

The type is a synonym for the template parameter A.

list::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.

list::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.

list::begin

   const_iterator begin() const;
   iterator begin();

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

list::clear

   void clear();

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

list::const_iterator

   typedef T1 const_iterator;

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

list::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.

list::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.

list::const_reverse_iterator

   typedef reverse_iterator<const_iterator>
       const_reverse_iterator;

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

list::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.

list::empty

   bool empty() const;

The member function returns true for an empty controlled sequence.

list::end

   const_iterator end() const;
   iterator end();

The member function returns a bidirectional iterator that points just beyond the end of the sequence.

list::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.

Erasing N elements causes N destructor calls. No reallocation occurs, so iterators and references become invalid only for the erased elements.

The member functions never throw an exception.

list::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.

list::get_allocator

   A get_allocator() const;

The member function returns the stored allocator object.

list::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.

Inserting N elements causes N constructor calls. No reallocation occurs, so no iterators or references become invalid.

If an exception is thrown during the insertion of one or more elements, the container is left unaltered and the exception is rethrown.

list::iterator

   typedef T0 iterator;

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

list::list

   list();
   explicit list(const A& al);
   explicit list(size_type n);
   list(size_type n, const T& v);
   list(size_type n, const T& v,
       const A& al);
   list(const list& x);
   template<class InIt>
       list(InIt first, InIt last);
   template<class InIt>
       list(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). None of the constructors perform any interim reallocations.

list::max_size

   size_type max_size() const;

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

list::merge

   void merge(list& x);
   template<class Pred>
       void merge(list& x, Pred pr);

Both member functions remove all elements from the sequence controlled by x and insert them in the controlled sequence. Both sequences must be ordered by the same predicate, described below. The resulting sequence is also ordered by that predicate.

No pairs of elements in the original controlled sequence are reversed in the resulting controlled sequence. If a pair of elements in the resulting controlled sequence compares equal (!(*Pi < *Pj) && !(*Pj < *Pi)), an element from the original controlled sequence appears before an element from the sequence controlled by x.

An exception occurs only if pr throws an exception. In that case, the controlled sequence is left in unspecified order and the exception is rethrown.

list::pointer

   typedef typename A::pointer pointer;

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

list::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.

list::pop_front

   void pop_front();

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

The member function never throws an exception.

list::push_back

   void push_back(const T& x);

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

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

list::push_front

   void push_front(const T& x);

The member function inserts an element with value x at the beginning of the controlled sequence.

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

list::rbegin

   const_reverse_iterator rbegin() const;
   reverse_iterator rbegin();

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

list::reference

   typedef typename A::reference reference;

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

list::remove

   void remove(const T& x);

The member function removes from the controlled sequence all elements, designated by the iterator P, for which *P == x.

The member function never throws an exception.

list::remove_if

   templace<class Pred>
       void remove_if(Pred pr);

The member function removes from the controlled sequence all elements, designated by the iterator P, for which pr(*P) is true.

An exception occurs only if pr throws an exception. In that case, the controlled sequence is left in an unspecified state and the exception is rethrown.

list::rend

   const_reverse_iterator rend() const;
   reverse_iterator rend();

The member function returns a reverse bidirectional 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.

list::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()).

list::reverse

   void reverse();

The member function reverses the order in which elements appear in the controlled sequence.

list::reverse_iterator

   typedef reverse_iterator<iterator>
       reverse_iterator;

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

list::size

   size_type size() const;

The member function returns the length of the controlled sequence.

list::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.

list::sort

   void sort();
   template<class Pred>
       void sort(Pred pr);

Both member functions order the elements in the controlled sequence by a predicate, described below.

For the iterators Pi and Pj designating elements at positions i and j, the first member function imposes the order !(*Pj < *Pi) whenever i < j. (The elements are sorted in ascending order.) The member template function imposes the order !pr(*Pj, *Pi) whenever i < j. No ordered pairs of elements in the original controlled sequence are reversed in the resulting controlled sequence. (The sort is stable.)

An exception occurs only if pr throws an exception. In that case, the controlled sequence is left in unspecified order and the exception is rethrown.

list::splice

   void splice(iterator it, list& x);
   void splice(iterator it, list& x, iterator first);
   void splice(iterator it, list& x, iterator first,
       iterator last);

The first member function inserts the sequence controlled by x before the element in the controlled sequence pointed to by it. It also removes all elements from x. (&x must not equal this.)

The second member function removes the element pointed to by first in the sequence controlled by x and inserts it before the element in the controlled sequence pointed to by it. (If it == first || it == ++first, no change occurs.)

The third member function inserts the subrange designated by [first, last) from the sequence controlled by x before the element in the controlled sequence pointed to by it. It also removes the original subrange from the sequence controlled by x. (If &x == this, the range [first, last) must not include the element pointed to by it.)

If the third member function inserts N elements, and &x != this, an object of class iterator is incremented N times. For all splice member functions, If get_allocator() == str.get_allocator(), no exception occurs. Otherwise, a copy and a destructor call also occur for each inserted element.

In all cases, only iterators or references that point at spliced elements become invalid.

list::swap

   void swap(list& 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.

list::unique

   void unique();
   template<class Pred>
       void unique(Pred pr);

The first member function removes from the controlled sequence every element that compares equal to its preceding element. For the iterators Pi and Pj designating elements at positions i and j, the second member function removes every element for which i + 1 == j && pr(*Pi, *Pj).

For a controlled sequence of length N (> 0), the predicate pr(*Pi, *Pj) is evaluated N - 1 times.

An exception occurs only if pr throws an exception. In that case, the controlled sequence is left in an unspecified state and the exception is rethrown.

list::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 list <T, A>& lhs,
           const list <T, A>& rhs);

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

operator==

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

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

operator<

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

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

operator<=

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

The template function returns !(rhs < lhs).

operator>

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

The template function returns rhs < lhs.

operator>=

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

The template function returns !(lhs < rhs).

swap

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

The template function executes lhs.swap(rhs).

References

algorithm() , memory(C++std)