std::end,std::cend (3) - Linux Manuals

std::end,std::cend: std::end,std::cend

NAME

std::end,std::cend - std::end,std::cend

Synopsis

Defined in header <iterator>
template< class C > (since C++11)
auto end( C& c ) -> decltype(c.end()); (until C++17)
template< class C > (since C++17)
constexpr auto end( C& c ) -> decltype(c.end());
template< class C > (since C++11)
auto end( const C& c ) -> decltype(c.end()); (until C++17)
template< class C > (since C++17)
constexpr auto end( const C& c ) -> decltype(c.end()); (1)
template< class T, std::size_t N > (since C++11)
T* end( T (&array)[N] ); (1) (until C++14)
template< class T, std::size_t N > (since C++14)
constexpr T* end( T (&array)[N] ) noexcept; (2)
template< class C >
constexpr auto cend( const C& c ) noexcept(/* see below */) (3) (since C++14)
-> decltype(std::end(c));

Returns an iterator to the end (i.e. the element after the last element) of the given container c or array array. These templates rely on C::end() having a reasonable implementation.
1) Returns exactly c.end(), which is typically an iterator one past the end of the sequence represented by c. If C is a standard Container, this returns a C::iterator when c is not const-qualified, and a C::const_iterator otherwise.
2) Returns a pointer to the end of the array array.
3) Returns exactly std::end(c), with c always treated as const-qualified. If C is a standard Container, this always returns a C::const_iterator.
 range-begin-end.svg

Parameters

c - a container with an end method
array - an array of arbitrary type

Return value

An iterator to the end of c or array. Note that the end of a container or array is defined as the element following the last valid element.

Exceptions

3)
noexcept specification:
noexcept(noexcept(std::end(c)))

Notes

In addition to being included in <iterator>, std::end and std::cend are guaranteed to become available if any of the following headers are included: <array>, <deque>, <forward_list>, <list>, <map>, <regex>, <set>
, <span>
(since C++20), <string>
, <string_view>
(since C++17), <unordered_map>, <unordered_set>, and <vector>.

User-defined overloads

Custom overloads of end may be provided for classes that do not expose a suitable end() member function, yet can be iterated. The following overloads are already provided by the standard library:

std::end(std::initializer_list) specializes std::end
                                                     (function template)
(C++11)

std::end(std::valarray) specializes std::end
                                                     (function template)
(C++11)
                                                     range-based for loop support
begin(std::filesystem::directory_iterator) (function)
end(std::filesystem::directory_iterator)
                                                     range-based for loop support
begin(std::filesystem::recursive_directory_iterator) (function)
end(std::filesystem::recursive_directory_iterator)

Similar to the use of swap (described in Swappable), typical use of the end function in generic context is an equivalent of using std::end; end(arg);, which lets both the ADL-selected overloads for user-defined types and the standard library function templates to appear in the same overload set.

  template<typename Container, typename Function>
  void for_each(Container&& cont, Function f) {
      using std::begin;
      auto it = begin(cont);
      using std::end;
      auto end_it = end(cont);
      while (it != end_it) {
          f(*it);
          ++it;
      }
  }

Example

// Run this code

  #include <iostream>
  #include <vector>
  #include <iterator>
  #include <algorithm>

  int main()
  {
      std::vector<int> v = { 3, 1, 4 };
      if (std::find(std::begin(v), std::end(v), 5) != std::end(v)) {
          std::cout << "found a 5 in vector v!\n";
      }

      int a[] = { 5, 10, 15 };
      if (std::find(std::begin(a), std::end(a), 5) != std::end(a)) {
          std::cout << "found a 5 in array a!\n";
      }
  }

Output:

  found a 5 in array a!