class PositionBlock;
class PositionBlockIterator;
 
class PositionBlockIterator{
    private:
        PositionBlock *posBlock;
 
    public:
        PositionBlockIterator(PositionBlock *posBlock_);
};
 
class PositionBlock {
    public:
        PositionBlockIterator * createIterator();
};
 
PositionBlockIterator::PositionBlockIterator(PositionBlock *posBlock_) {
    posBlock = posBlock_;
}
 
PositionBlockIterator * PositionBlock::createIterator(){
    return new PositionBlockIterator(this);
}
 
int main() {}

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