std::array::back

reference back();		(until C++17)
constexpr reference back();		(since C++17)
const_reference back() const;		(until C++14)
constexpr const_reference back() const;		(since C++14)

Returns reference to the last element in the container.

Calling back on an empty container is undefined.

Parameters

(none)

Return value

Reference to the last element.

Complexity

Constant.

Notes

For a container c, the expression return c.back(); is equivalent to { auto tmp = c.end(); --tmp; return *tmp; }

Example

The following code uses back to display the last element of a std::array<char>:

Run this code

#include <array>
#include <iostream>
 
int main()
{
    std::array<char, 6> letters {'o', 'm', 'g', 'w', 't', 'f'};
    if (!letters.empty()) {
        std::cout << "The last character is: " << letters.back() << '\n';
    }  
}

Output:

The last character is f

Language
Standard library headers
Concepts
Utilities library
Strings library
Containers library
Algorithms library
Iterators library
Numerics library
Input/output library
Localizations library
Regular expressions library (C++11)
Atomic operations library (C++11)
Thread support library (C++11)
Filesystem library (C++17)
Technical Specifications

array (C++11)
vector
deque
forward_list (C++11)
list
set
multiset
map
multimap
unordered_set (C++11)
unordered_multiset (C++11)
unordered_map (C++11)
unordered_multimap (C++11)
stack
queue
priority_queue