Implement Stack using Queues

Description:

Implement the following operations of a stack using queues.

• push(x) -- Push element x onto stack.
• pop() -- Removes the element on top of the stack.
• top() -- Get the top element.
• empty() -- Return whether the stack is empty.

Notes:

• You must use only standard operations of a queue -- which means only push to back, peek/pop from front, size, and is emptyoperations are valid.
• Depending on your language, queue may not be supported natively. You may simulate a queue by using a list or deque (double-ended queue), as long as you use only standard operations of a queue.
• You may assume that all operations are valid (for example, no pop or top operations will be called on an empty stack).

Code:

class Stack {
public:
    // Push element x onto stack.
    void push(int x) {
        m.push_front(x);
    }

    // Removes the element on top of the stack.
    void pop() {
        if (!m.empty())
            m.pop_front(); 
    }

    // Get the top element.
    int top() {
        if (!m.empty())
            return m.front();
    }

    // Return whether the stack is empty.
    bool empty() {
       if (m.size()==0)
        return true;
       else
        return false;
    }
    private:
    deque<int>m;
};