how to print out all elements in a std::stack or std::queue conveniently

Question

If I do not to want to create a new container in order to do so?

Answer 1

1. If you need to do this, then stack or queue is not the correct choice of container.
2. If you still insist on doing this, the best way is to make a copy and pop elements off of it and print them. I'm not going to suggest another way because there's no point.

Answer 2

It can be easily done using recursion you just need to know when to re-add the next element

For Stack

void print(stack<char> &s)
{
    if(s.empty())
    {
        cout << endl;
        return;
    }
    char x= s.top();
    s.pop();
    print(s);
    s.push(x);
    cout << x << " ";
 }

And this one is For Queue

void print(queue<char> &s,int num)
{
    if(!num)
    {
        cout << endl;
        return;
    }
    char x= s.front();
    s.pop();
    cout << x << " ";
    s.push(x);
    print(s,--num);
}

Good Luck