std::forward_list<T,Allocator>::begin, std::forward_list<T,Allocator>::cbegin
From cppreference.com
< cpp | container | forward list
| iterator begin() noexcept; |
(since C++11) | |
| const_iterator begin() const noexcept; |
(since C++11) | |
| const_iterator cbegin() const noexcept; |
(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
| (C++11) |
returns an iterator to the end (public member function) |
| (C++11)(C++14) |
returns an iterator to the beginning of a container or array (function template) |