LeetCode "Peeking Iterator"

class PeekingIterator : public Iterator {
    bool bPeeked;
    int val;
public:
    PeekingIterator(const vector<int>& nums) : Iterator(nums) {
        val = -1;
        bPeeked = false;
    }

    // Returns the next element in the iteration without advancing the iterator.
    int peek() {
        if (!bPeeked)
        {
            val = Iterator::next();
            bPeeked = true;
        }
        return val;
    }

    // hasNext() and next() should behave the same as in the Iterator interface.
    // Override them if needed.
    int next() {
        if (bPeeked)
        {
            bPeeked = false;
            return val;
        }
        return Iterator::next();
    }

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