cend() Function in C++

Cend() is the function defined in C++ STL. This function produces a constant random access iterator that identifies the deque’s past-the-end element. If the container is empty then cend() function returns the same as cbegin() function. This member function’s iterator can only be used to iterate containers; it cannot be used to change the content of the object it is pointing at. 

Syntax:

const_iterator cend() const noexcept;

A const_iterator is an iterator that points to constant content.

Example 1: Below is the C program to use cend() function in deque to print elements in reverse order:

C++

// C++ code demonstrating the use
// of cend() function in deque
// to print elements in reverse
// order.
#include <iostream>
#include <deque>
using namespace std;

// Driver code
int main()
{
  // Initialising the deque
  deque<int> d = {1, 2, 3, 4, 5};

  cout << "Elements of deque in reverse order: " <<
           endl;
  for (auto it = d.cend() - 1;
            it >= d.cbegin(); --it)
    cout << *it << " ";

  cout << endl;
  return 0;
}

Output

Elements of deque in reverse order: 
5 4 3 2 1 

• Time Complexity: O(n) where n is the number of elements in the deque.
• Auxiliary Space: O(1)

Example 2: Below is the C program to use cend() function in deque to print elements of deque:

C++

// C++ code demonstrating the use
// of cend() function in deque
// to print elements of deque
#include <iostream>
#include <deque>
using namespace std;

// Driver code
int main()
{
  // Initialising the deque
  deque<string> d = {"geeks","for","geeks"};

  auto itr = d.cbegin();

  // Printing the deque with
  // help of cend() function
  while(itr != d.cend())
  {
    cout << *itr;
    cout << " ";
    ++itr;
  }
  return 0;
}

Output

geeks for geeks 

• Time Complexity: O(n) where n is the number of elements in the deque.
• Auxiliary Space: O(1)