OpenEmailGenerator/Stack_using_queue.cpp at main · ManishSah26/OpenEmailGenerator · GitHub

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#include <bits/stdc++.h>
using namespace std;

class Stack
{
    queue<int> q1, q2;

public:
    void push(int x)
    {

        q2.push(x);
        while (!q1.empty())
        {
            q2.push(q1.front());
            q1.pop();
        }
        queue<int> q = q1;
        q1 = q2;
        q2 = q;
    }
    void pop()
    {
        if (q1.empty())
            return;
        q1.pop();
    }
    int top()
    {
        if (q1.empty())
            return -1;
        return q1.front();
    }
    int size() { return q1.size(); }
};

int main()
{
    Stack s;
    s.push(1);
    s.push(2);
    s.push(3);
    cout << "current size: " << s.size() << endl;
    cout << s.top() << endl;
    s.pop();
    cout << s.top() << endl;
    s.pop();
    cout << s.top() << endl;
    cout << "current size: " << s.size() << endl;
    return 0;
}