C++ Library - <list>


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Introduction

List is a popularly used sequence container. Container is an object that holds data of same type. List container is implemented as doubly linked-list, hence it provides bidirectional sequential access to it's data.

List doesn't provide fast random access, it only supports sequential access in both directions. List allows insertion and deletion operation anywhere within a sequence in constant time.

Elements of list can be scattered in different chunks of memory. Container stores necessary information to allow sequential access to it's data. Lists can shrink or expand as needed from both ends at run time. The storage requirement is fulfilled automatically by internal allocator.

Zero sized lists are also valid. In that case list.begin() and list.end() points to same location. But behavior of calling front() or back() is undefined.

Definition

Below is definition of std::list from <list> header file

template < class T, class Alloc = allocator<T> > class list;

Parameters

  • T − Type of the element contained.

    T may be substituted by any other data type including user-defined type.

  • Alloc − Type of allocator object.

    By default, the allocator class template is used, which defines the simplest memory allocation model and is value-independent.

Member types

Following member types can be used as parameters or return type by member functions.

Sr.No. Member types Definition
1 value_type T (First parameter of the template)
2 allocator_type Alloc (Second parameter of the template)
3 reference value_type&
4 const_reference const value_type&
5 pointer value_type*
6 const_pointer const value_type*
7 iterator a random access iterator to value_type
8 const_iterator a random access iterator to const value_type
9 reverse_iterator std::reverse_iterator <iterator>
10 const_reverse_iterator std::reverse_iterator <const_iterator>
11 size_type size_t
12 difference_type ptrdiff_t

Functions from <list>

Below is list of all methods from <list> header.

Constructors

Sr.No. Method & Description
1 list::list default constructor

Constructs an empty list with zero elements.

2 list::list fill constructor

Constructs a new list with n elements and assigns val to each element of list.

3 list::list fill constructor

Constructs a new list with n elements and assign zero value to each element of list.

4 list::list range constructor

Constructs a list with as many elements as in range of first to last.

5 list::list copy constructor

Constructs a list with copy of each elements present in existing list.

6 list::list move constructor

Constructs a list with the contents of other using move semantics.

7 list::list initializer list constructor

Constructs a list with the contents of other using move semantics.

Destructor

Sr.No. Method & Description
1 list::~list

Destroys list object by deallocating it's memory.

Member functions

Sr.No. Method & Description
1 list::assign range version

Assigns new value to list by replacing old ones.

2 list::assign fill version

Assigns new values to list by replacing old ones.

3 list::assign initializer list version

Assigns new values to list by replacing old ones.

4 list::back

Returns a reference to the last element of the list.

5 list::begin

Returns a random access iterator which points to the first element of the list.

6 list::cbegin

Returns a constant random access iterator which points to the beginning of the list.

7 list::cend

Returns a constant random access iterator which points to the end of the list.

8 list::clear

Destroys the list by removing all elements from the list and sets size of list to zero.

9 list::crbegin

Returns a constant reverse iterator which points to the last element of the list.

10 list::crend

Returns a constant reverse iterator which points to the theoretical element preceding the first element in the list.

11 list::emplace

Extends list by inserting new element at a given position.

12 list::emplace_back

Inserts new element at the end of list and increases size of list by one.

13 list::emplace_front

Inserts new element at the beginning of the list and increases size of list by one.

14 list::empty

Tests whether list is empty or not.

15 list::end

Returns a random access iterator which points to the last element of the list.

16 list::erase position version

Removes single element from the the list.

17 list::erase range version

Removes range of element from the the list.

18 list::front

Returns a reference to the first element of the list.

19 list::get_allocator

Returns an allocator associated with list

20 list::insert single element version

Extends iterator by inserting new element at position in list.

21 list::insert fill version

Extends list by inserting new elements in the container.

22 list::insert range version

Extends list by inserting new elements in the container.

23 list::insert move version

Extends list by inserting new element in the container.

24 list::insert initializer list version

Extends list by inserting new elements in the container

25 list::max_size

Returns the maximum number of elements can be held by list.

26 list::merge

Merges two sorted lists into one.

27 list::merge compare function

Merges two sorted lists into one.

28 list::merge move version

Merges two sorted lists into one by using move semantics.

29 list::merge compare function move version

Merges two sorted lists into one by using move semantics.

30 list::operator= copy version

Assigns new contents to the list by replacing old ones.

31 list::operator= move version

Assign new contents to the list by replacing old ones.

32 list::operator= initializer list version

Assign new contents to the list by replacing old ones.

33 list::pop_back

Removes last element from list.

34 list::pop_front

Removes first element from list.

35 list::push_back

Inserts new element at the end of list.

36 list::push_back move version

Inserts new element at the end of list.

37 list::push_front

Inserts new element at the beginning of list.

38 list::push_front move version

Inserts new element at the beginning of list.

39 list::rbegin

Returns a reverse iterator which points to the last element of the list.

40 list::remove

removes element(s) from the list that matches the value.

41 list::remove_if

removes elements from the list that fulfills the condition.

42 list::rend

Returns a reverse iterator which points to the reverse end of the list.

43 list::resize

Changes the size of list.

44 list::resize value version

Changes the size of list.

45 list::reverse

Reverses the order of the elements present in the list.

46 list::size

Returns the number of elements present in the list.

47 list::sort

Sorts the elements of the list.

48 list::sort compare function

Sorts the elements of the list.

49 list::splice

Transfers all elements from list to *this.

50 list::splice single element

Transfers a element pointed to by iterator i from list x into *this.

51 list::splice move version

Transfers all elements from list x to *this by using move semantics.

52 list::splice range version

Transfers the elements in the range of first to last from x to *this.

53 list::splice single element move version

Transfers the element pointed to by iterator i from list x into *this by using move semantics.

54 list::splice range and move version

Transfers the elements in the range of first to last from x to *this by using move semantics.

55 list::swap

Exchanges the content of list with contents of another list x.

56 list::unique

Removes all consecutive duplicate elements from the list.

57 list::unique

Removes all consecutive duplicate elements from the list.

Non-member overloaded functions

Sr.No. Method & Description
1 operator==

Tests whether two lists are equal or not.

2 operator!=

Tests whether two lists are equal or not.

3 operator<

Tests whether first list is less than other or not.

4 operator<=

Tests whether first list is less than or equal to other or not.

5 operator>

Tests whether first list is greater than other or not.

6 operator>=

Tests whether first list is greater than or equal to other or not.

7 swap

Exchanges the contents of two list.



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