C++ <iterator> - end() Function

The C++ <iterator> end() function returns an iterator pointing to the past-the-last element in the sequence.

• Container: If the container's object is constant qualified, the function returns a const_iterator, else returns an iterator.
• Array: The function returns a pointer to the end of the array.

The past-the-last element of a sequence is the theoretical element that follows the last element. It does not point to any element, and hence could not be dereferenced.

These function templates are defined in multiple headers which are: <iterator>, <array>, <deque>, <forward_list>, <list>, <map>, <regex>, <set>, <string>, <string_view>, <unordered_map>, <unordered_set> and <vector>.

Along with this, this function is overloaded with a different definition in headers <initializer_list> and <valarray>.

Syntax

• C++11
• C++14
• C++17

//container version
template <class Container>
  auto end (Container& cont) 
    -> decltype (cont.end());
template <class Container>
  auto end (const Container& cont) 
    -> decltype (cont.end());

//array version
template <class T, size_t N>
  T* end (T(&arr)[N]);

//container version
template <class Container>
  auto end (Container& cont) 
    -> decltype (cont.end());
template <class Container>
  auto end (const Container& cont) 
    -> decltype (cont.end());

//array version
template <class T, size_t N>
  constexpr T* end (T(&arr)[N]) noexcept;

//container version
template <class Container>
  constexpr auto end (Container& cont) 
    -> decltype (cont.end());
template <class Container>
  constexpr auto end (const Container& cont) 
    -> decltype (cont.end());

//array version
template <class T, size_t N>
  constexpr T* end (T(&arr)[N]) noexcept;

Parameters

Return Value

Returns an iterator to the past-the-last element of the sequence:

• Container: If the container's object is constant qualified, the function returns a const_iterator, else returns an iterator.
• Array: The function returns a pointer to the end of the array.

Example:

In the example below, the end() function is used to iterate over an array to insert all elements of the array into a vector.

#include <iostream>
#include <iterator>
#include <vector>
using namespace std;
 
int main (){
  int arr[] = {10, 20, 30, 40, 50};
  vector<int> vec;

  //iterate over array to insert all elements
  //of the array into an empty vector
  for(auto it = begin(arr); it != end(arr); ++it)
    vec.push_back(*it);

  //print the content of the vector
  cout<<"vec contains: ";
  for(auto it = begin(vec); it != end(vec); ++it)
    cout<<*it<<" ";

  return 0;
}

The output of the above code will be:

vec contains: 10 20 30 40 50