std::forward_list<T,Allocator>::begin,std::forward_list<T,Allocator>::cbegin (3) - Linux Manuals

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

NAME

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

Synopsis

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 container.
If the container is empty, the returned iterator will be equal to end().
 range-begin-end.svg

Parameters

(none)

Return value

Iterator to the first element

Complexity

Constant

Example

// Run this code

  #include <iostream>
  #include <forward_list>
  #include <string>

  int main()
  {
   std::forward_list<int> ints {1, 2, 4, 8, 16};

   std::forward_list<std::string> fruits {"orange", "apple", "raspberry"};

   std::forward_list<char> empty;

   // Sums all integers in the forward_list ints (if any), printing only the result.

   int sum = 0;

   for (auto it = ints.cbegin(); it != ints.cend(); it++)

   sum += *it;

   std::cout << "Sum of ints: " << sum << "\n";

   // Prints the first fruit in the forward_list fruits, without checking if there is one.

   std::cout << "First fruit: " << *fruits.begin() << "\n";

   if (empty.begin() == empty.end())

   std::cout << "forward_list 'empty' is indeed empty.\n";

  }

Output:

  Sum of ints: 31
  First fruit: orange
  forward_list 'empty' is indeed empty.