Can you explain what is meant by a bidirectional iterator in the context of C++?

A bidirectional iterator in C++ is an iterator that supports moving both forward and backward through a container. Unlike unidirectional (input or forward) iterators, bidirectional iterators allow the use of ++ and -- operators to move to the next and previous elements, respectively.

Example of using a bidirectional iterator with std::list:

#include <iostream>
#include <list>

int main() {
    std::list<int> lst = {1, 2, 3, 4};
    auto it = lst.begin();

    ++it; // move to the second element (2)
    std::cout << *it << "\n";

    --it; // move back to the first element (1)
    std::cout << *it << "\n";

    return 0;
}

Bidirectional iterators are typically supported in containers where bidirectional navigation is possible, such as std::list, std::set, std::map.