value_type& back();
const value_type& back() const;

#include <iostream>
#include <queue>
int main()
{
    std::queue<int> newqueue;
    newqueue.push(24);
    newqueue.push(80);
    newqueue.back () += newqueue.front();
    std::cout <<"newqueue.back() is modified to" << newqueue.back ();
    return 0;
}

newqueue.back() is modified to 104