std::forward_list<T,Allocator>::begin, std::forward_list<T,Allocator>::cbegin

 

C++

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Technical specifications

Symbols index

External libraries

 

Containers library

Sequence

array (C++11)

vector

vector<bool>

inplace_vector (C++26)

deque

forward_list (C++11)

list

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set

multiset

map

multimap

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unordered_set (C++11)

unordered_multiset (C++11)

unordered_map (C++11)

unordered_multimap (C++11)

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stack

queue

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flat_map (C++23)

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span (C++20)

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std::forward_list

Member functions
forward_list::forward_list forward_list::~forward_list forward_list::operator= forward_list::assign forward_list::assign_range (C++23)   forward_list::get_allocator Element access forward_list::front Iterators forward_list::before_beginforward_list::cbefore_begin forward_list::beginforward_list::cbegin forward_list::endforward_list::cend Capacity forward_list::empty forward_list::max_size	Modifiers forward_list::clear forward_list::emplace_front forward_list::push_front forward_list::insert_after forward_list::emplace_after forward_list::erase_after forward_list::insert_range_after (C++23) forward_list::prepend_range (C++23) forward_list::pop_front forward_list::resize forward_list::swap Operations forward_list::merge forward_list::splice_after forward_list::removeforward_list::remove_if forward_list::reverse forward_list::unique forward_list::sort
Non-member functions
operator==operator<=> (C++20) swap(std::forward_list) erase(std::forward_list)erase_if(std::forward_list) (C++20)(C++20)	operator!=operator<operator>operator<=operator>= (until C++20)(until C++20)(until C++20)(until C++20)(until C++20)
Deduction guides (C++17)

 

iterator begin() noexcept;	(1)	(since C++11)
const_iterator begin() const noexcept;	(2)	(since C++11)
const_iterator cbegin() const noexcept;	(3)	(since C++11)

Returns an iterator to the first element of the forward_list.

If the forward_list is empty, the returned iterator will be equal to end().

Parameters

(none)

Return value

Iterator to the first element.

Complexity

Constant.

Example

Run this code

#include <algorithm>
#include <iostream>
#include <numeric>
#include <string>
#include <forward_list>
 
int main()
{
    std::forward_list<int> nums{1, 2, 4, 8, 16};
    std::forward_list<std::string> fruits{"orange", "apple", "raspberry"};
    std::forward_list<char> empty;
 
    // Print forward_list.
    std::for_each(nums.begin(), nums.end(), [](const int n) { std::cout << n << ' '; });
    std::cout << '\n';
 
    // Sums all integers in the forward_list nums (if any), printing only the result.
    std::cout << "Sum of nums: "
              << std::accumulate(nums.begin(), nums.end(), 0) << '\n';
 
    // Prints the first fruit in the forward_list fruits, checking if there is any.
    if (!fruits.empty())
        std::cout << "First fruit: " << *fruits.begin() << '\n';
 
    if (empty.begin() == empty.end())
        std::cout << "forward_list 'empty' is indeed empty.\n";
}

Output:

1 2 4 8 16
Sum of nums: 31
First fruit: orange
forward_list 'empty' is indeed empty.

See also

endcend	returns an iterator to the end (public member function)
begincbegin (C++11)(C++14)	returns an iterator to the beginning of a container or array (function template)