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Introduction
forward_list is a popularly used sequence container. Container is an object that holds data of same type. forward_list container is implemented as singly linked-list, hence it provides unidirectional sequential access to it”s data.
forward_list doesn”t provide fast random access, it only supports sequential access in only one directions. forward_list allows insertion and deletion operation anywhere within a sequence in constant time.
Elements of forward_list can be scattered in different chunks of memory. Container stores necessary information to allow sequential access to it”s data. forward_lists can shrink or expand as needed from both ends at run time. The storage requirement is fulfilled automatically by internal allocator.
Zero sized forward_lists are also valid. In that case forward_list.begin() and forward_list.end() points to same location. But behavior of calling front() is undefined.
Definition
Below is definition of std::forward_list from <forward_list> header file
template < class T, class Alloc = allocator<T> > class forward_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 | size_type | size_t |
10 | difference_type | ptrdiff_t |
Functions from <forward_list>
Below is list of all methods from <forward_list> header.
Constructors
Sr.No. | Method & Description |
---|---|
1 | forward_list::forward_list default constructor
Constructs an empty forward_list with zero elements. |
2 | forward_list::forward_list fill constructor
Constructs a new forward_list with n elements and assigns val to each element of forward_list. |
3 | forward_list::forward_list fill constructor
Constructs a new forward_list with n elements and assign zero value to each element of forward_list. |
4 | forward_list::forward_list range constructor
Constructs a forward_list with as many elements as in range of first to last. |
5 | forward_list::forward_list copy constructor
Constructs a forward_list with copy of each elements present in existing list. |
6 | forward_list::forward_list move constructor
Constructs a forward_list with the contents of other using move semantics. |
7 | forward_list::forward_list initializer list constructor
Constructs a forward_list from initialize list. |
Destructor
Sr.No. | Method & Description |
---|---|
1 | forward_list::~forward_list
Destroys forward_list object by deallocating it”s memory. |
Member functions
Sr.No. | Method & Description |
---|---|
1 | forward_list::assign range version
Assigns new value to forward_list by replacing old ones. |
2 | forward_list::assign fill version
Assigns new values to forward_list by replacing old ones. |
3 | forward_list::assign initializer list version
Assigns new values to forward_list by replacing old ones. |
4 | forward_list::before_begin
Returns a random access iterator which points to the position before the first element of the forward_list. |
5 | forward_list::begin
Returns a random access iterator which points to the first element of the forward_list. |
6 | forward_list::cbefore_begin
Returns a constant random access iterator which points to the position before the first element of the forward_list. |
7 | forward_list::cbegin
Returns a constant random access iterator which points to the beginning of the forward_list. |
8 | forward_list::cend
Returns a constant random access iterator which points to the end of the forward_list. |
9 | forward_list::clear
Destroys the forward_list by removing all elements from the forward_list and sets size of forward_list to zero. |
10 | forward_list::emplace_after
Constructs and inserts new element after position in the forward_list and increases size of forward_list by one. |
11 | forward_list::emplace_front
Inserts new element at the beginning of the forward_list and increases size of forward_list by one. |
12 | forward_list::empty
Tests whether forward_list is empty or not. |
13 | forward_list::end
Returns a random access iterator which points to the last element of the forward_list. |
14 | forward_list::erase_after position version
Removes single element after position from the the forward_list. |
15 | forward_list::erase range version
Removes range of element from the the forward_list. |
16 | forward_list::front
Returns a reference to the first element of the forward_list. |
17 | forward_list::get_allocator
Returns an allocator associated with forward_list |
18 | forward_list::insert_after single element version
Extends iterator by inserting new element after position in forward_list |
19 | forward_list::insert_after move version
Extends iterator by inserting new element after position in forward_list |
20 | forward_list::insert_after fill version
Extends iterator by inserting new element after position in forward_list |
21 | forward_list::insert_after range version
Extends iterator by inserting new element after position in forward_list |
22 | forward_list::insert_after initializer list version
Extends iterator by inserting new element after position in forward_list |
23 | forward_list::max_size
Returns the maximum number of elements can be held by forward_list. |
24 | forward_list::merge
Merges two sorted forward_lists into one. |
25 | forward_list::merge move version
Merges two sorted forward_lists into one. |
26 | forward_list::merge compare function
Merges two sorted forward_lists into one. |
27 | forward_list::merge compare function move version
Merges two sorted forward_lists into one by using move semantics. |
28 | forward_list::operator= copy version
Assigns new contents to the forward_list by replacing old ones. |
29 | forward_list::operator= move version
Assign new contents to the forward_list by replacing old ones. |
30 | forward_list::operator= initializer list version
Assign new contents to the forward_list by replacing old ones. |
31 | forward_list::pop_front
Removes first element from forward_list. |
32 | forward_list::push_front copy version
Inserts new element at the beginning of forward_list. |
33 | forward_list::push_front move version
Inserts new element at the beginning of forward_list. |
34 | forward_list::remove
removes element(s) from the forward_list that matches the value. |
35 | forward_list::remove_if
removes elements from the forward_list that fulfills the condition. |
36 | forward_list::resize
Changes the size of forward_list. |
37 | forward_list::resize value version
Changes the size of forward_list. |
38 | forward_list::reverse
Reverses the order of the elements present in the forward_list. |
39 | forward_list::sort
Sorts the elements of the forward_list. |
40 | forward_list::sort compare function
Sorts the elements of the forward_list. |
41 | forward_list::splice_after
Transfers all elements from forward_list to *this. |
42 | forward_list::splice_after move version
Transfers all elements from forward_list x to *this by using move semantics. |
43 | forward_list::splice_after single element
Transfers a element pointed to by iterator i from forward_list x into *this. |
44 | forward_list::splice_after single element move version
Transfers the element pointed to by iterator i from forward_list x into *this by using move semantics. |
45 | forward_list::splice_after range version
Transfers the elements in the range of first to last from x to *this. |
46 | forward_list::splice range and move version
Transfers the elements in the range of first to last from x to *this by using move semantics. |
47 | forward_list::swap
Exchanges the content of a forward_list with contents of another forward_list x. |
48 | forward_list::unique
Removes all consecutive duplicate elements from the forward_list. |
49 | forward_list::unique
Removes all consecutive duplicate elements from the forward_list. |
Non-member overloaded functions
Sr.No. | Method & Description |
---|---|
1 | operator==
Tests whether two forward_lists are equal or not. |
2 | operator!=
Tests whether two forward_lists are equal or not. |
3 | operator<
Tests whether first forward_list is less than other or not. |
4 | operator<=
Tests whether first forward_list is less than or equal to other or not. |
5 | operator>
Tests whether first forward_list is greater than other or not. |
6 | operator>=
Tests whether first forward_list is greater than or equal to other or not. |
7 | swap
Exchanges the contents of two forward_list. |
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