std::deque::back(3)

🎀 NAME 🎀

okay bestie, this is std::deque::back from the C++ Standard Libary manual, page std::deque::back(3). The NAME line is literally std::deque::back - std::deque::back — yes, that’s the whole name, and it’s iconic. 💅

✨ Synopsis ✨

reference back();             (1)
const_reference back() const; (2)

This one returns a reference to the last element in the container. That’s the main character move. 🫶

Bestie, listen: calling back on an empty container causes undefined behavior. That is not a vibe, not a little oops — literally undefined behavior, periodt. 💀

🌸 Parameters 🌸

(none) — no parameters, no extra homework. ✨

💖 Return value 💖

A reference to the last element. That’s it, that’s the return value. 🎀

🦋 Complexity 🦋

Constant. Lowkey the shortest flex on the whole page. ⭐

🧚 Notes 🧚

For a non-empty container c, the expression c.back() is equivalent to *std::prev(c.end()). No cap, that’s the exact equivalence. 🌈

🌈 Example 🌈

The example uses back to display the last element of a std::deque<char>. Run this code:

        #include <deque>
        #include <iostream>

        int main()
        {
            std::deque<char> letters{'a', 'b', 'c', 'd', 'e', 'f'};

            if (!letters.empty())
                std::cout << "The last character is '" << letters.back() <<
       "'.\n";
        }

Output:

The last character is 'f'.

💅 See also 💅

• front — access the first element (public member function).

🌸 source/version/date sign-off: http://cppreference.com · 2024.06.10 · std::deque::back(3) — mwah, bye bestie! 💖