template <class TData>
class PatternIterator
{
    virtual bool hasNext() = 0;
    virtual TData next() = 0;
    virtual TData& operator* () = 0;
 };

template <class TKey>
class KHashTablePatternIterator : public PatternIterator<TKey>
{
    int usedElems;
    int pos;
    friend KHashTable <TKey>;
    KHashTable <TKey> hashTable;
public:
    KHashTablePatternIterator(KHashTable<TKey> &obj) : pos (0), usedElems(0), hashTable(obj) {}
    TKey next() {
        while (!hashTable.isUsed[pos]) { pos++; }
        TKey curElem = hashTable.table[pos];
        pos++;
        usedElems++;
        return curElem;
    }
    TKey& operator* () {
        while (!hashTable.isUsed[pos]) { pos++; }
        return hashTable.table[pos];
    }
    bool hasNext() { if (usedElems == hashTable.nSize) return false; else return true; }

};