Templates&Exclusions

#include <iostream>
#include <vector>

using namespace std;

template <int N, class T>
class queue {
    private:
        vector<T> vec;
        int max_size;
    public:
        queue()
        {
            max_size = N;
        }
        class overflow {};
        class empty {};

        void push(T value)
        {
            if (vec.size() == max_size)
                throw overflow();
            else
                vec.push_back(value);
        }

        T pop()
        {
            if (vec.empty()) {
                throw empty();
            } else {
                T value = vec[0];
                vec.erase(vec.begin() + 0);

                return value;
            }
        }
};

int main()
{
    queue<2, int> q;

    try {
        cout << q.pop() << endl;
    }
    catch (queue<2, int>::empty err) {
        cout << " ***Queue is Empty ***" << endl;
    }

    q.push(42);
    q.push(420);

    try {
        q.push(228);
    }
    catch (queue<2, int>::overflow err) {
        cout << " ***Queue Overflow ***" << endl;
    }

    cout << q.pop() << endl;
    cout << q.pop() << endl;

    q.push(150); // see?
    q.push(500);
    //q.push(700); NO

    return 0;
}