A forward list is a sequence container that stores data of same type. List container is implemented as singly-linked lists, hence provides sequential access of its data. It also allow constant time insertion and deletion operations anywhere within the sequence. Please note that, forward_list can only be iterated forwards.
The forward_list supports shrink and expand functionality at runtime, hence, list requires more memory and in return it manage memory dynamically and efficiently.
The main disadvantage of using list and forward_list as compared to other sequence container is that they lack direct access of any elements by its position, for example - using operator []. To access any element in a forward_list, iteration need to be done from a known position (like beginning or end of the list) to the element's position, which takes linear time to access element.
Syntax
template < class T, class Alloc = allocator<T> > class forward_list;
Parameters
T |
Type of the elements stored in the container. |
Alloc |
Type of the allocator object used to define the storage allocation model. default: allocator. |
Member Types
| Member types | Definition |
|---|
| value_type | T (First template parameter) |
| allocator_type | Alloc (Second template parameter), default: allocator<value_type> |
| reference | value_type& |
| const_reference | const value_type& |
| pointer | Alloc::pointer, default: value_type* |
| const_pointer | Alloc::const_pointer, default: value_type* |
| iterator | a forward iterator to const value_type, convertible to const_iterator |
| const_iterator | a forward iterator to const value_type |
| difference_type | ptrdiff_t |
| size_type | size_t |
The C++ forward_list container has a number of member functions which are listed below:
| Functions | Description |
|---|
| empty() |
Checks whether the forward_list is empty or not. |
| max_size() |
Returns the maximum length of the forward_list. |
| Functions | Description |
|---|
| front() |
Access first element of the forward_list. |
| Functions | Description |
|---|
| before_begin() |
Returns iterator pointing to the before-the-first element of the forward_list. |
| begin() |
Returns iterator pointing to the first element of the forward_list. |
| end() |
Returns iterator pointing to the past-the-last element of the forward_list. |
| cbefore_begin() |
Returns const_iterator pointing to the before-the-first element of the forward_list. |
| cbegin() |
Returns const_iterator pointing to the first element of the forward_list. |
| cend() |
Returns const_iterator pointing to the past-the-last element of the forward_list. |
| Functions | Description |
|---|
| assign() |
Assign forward_list content. |
| clear() |
Clears all elements of the forward_list. |
| pop_front() |
Deletes first element of the forward_list. |
| push_front() |
Adds a new element at the beginning of the forward_list. |
| emplace_front() |
Constructs and inserts a new element at the beginning of the forward_list. |
| emplace_after() |
Constructs and inserts a new element at the specified position in the forward_list. |
| erase_after() |
Deletes an element or range of elements from the forward_list. |
| insert_after() |
Inserts a new element or range of elements in the forward_list. |
| resize() |
Changes the size of the forward_list by specified number of elements. |
| swap() |
Exchanges elements between two forward_lists. |
| Functions | Description |
|---|
| merge() |
Merge two sorted forward_lists into one. |
| splice_after() |
Transfers elements from one forward_list to another forward_list. |
| remove() |
Delete all occurrences of specified element from the forward_list. |
| remove_if() |
Delete all elements from a forward_list based on specified condition. |
| reverse() |
Reverse the order of elements of the forward_list container. |
| sort() |
Sorts all elements of a forward_list. |
| unique() |
Deletes all consecutive duplicate elements from a forward_list. |
| Functions | Description |
|---|
| get_allocator() |
Return a copy of allocator object associated with the forward_list. |
| Functions | Description |
|---|
| operator == |
Checks whether two forward_lists are equal or not. |
| operator != |
Checks whether two forward_lists are unequal or not. |
| operator < |
Checks whether the first forward_list is less than the other or not. |
| operator > |
Checks whether the first forward_list is greater than the other or not. |
| operator <= |
Checks whether the first forward_list is less than or equal to the other or not. |
| operator >= |
Checks whether the first forward_list is greater than or equal to the other or not. |
| swap() |
Exchanges elements between two forward_lists. |
