class Functor
{
public:
    // The constructor.
    explicit Functor(int& evenCount)
        : _evenCount(evenCount)
    {
        //_evenCount = evenCount;
    }
    // The function-call operator prints whether the number is
    // even or odd. If the number is even, this method updates
    // the counter.
    void operator()(int n)
    {
        cout << n;
        if (n % 2 == 0)
        {
            cout << " is even " << endl;
            // Increment the counter.
            _evenCount++;
        }
        else
        {
            cout << " is odd " << endl;
        }
    }
private:
    int& _evenCount; // the number of even variables in the vector
};