284. Peeking Iterator

class PeekingIterator : public Iterator
{
public:
    PeekingIterator(const vector<int> &nums) : Iterator(nums)
    {
    }

    int peek()
    {
        return Iterator(*this).next();
    }

    int next()
    {
        return Iterator::next();
    }

    bool hasNext() const
    {
        return Iterator::hasNext();
    }
};