#include <iostream>

#include <queue>

using namespace std;

​

int main() {

  // Create a queue of strings

  queue<string> cars;

​

  // Add elements to the queue

  cars.push("Volvo");

  cars.push("BMW");

  cars.push("Ford");

  cars.push("Mazda");

  // Change the value of the front element

  cars.front() = "Tesla";

​

  // Change the value of the back element

  cars.back() = "VW";

​

  // Access the front element

  cout << cars.front() << "\n";

​

  // Access the back element

  cout << cars.back() << "\n";

  return 0;

}

​