Using template value inside nested class - c++

Question

I have the following class definition:
template <int B>
class SparseBitvector
{
typedef typename std::vector<std::bitset<B>> BitsetVector;
public:
class iterator: public std::iterator<...>
{
public:
explicit iterator(..., BitsetVector::iterator* _chunksIt, ...) {...}
}
}
At compilation I get this error:
/project/powerset/src/powerset/sparse_bitvector.h:96:125: error: 'std::BitsetVector<std::bitset<(long unsigned int)B>, std::allocator<std::bitset<(long unsigned int)B> > >::iterator' is not a type
explicit iterator(SortedStaticSet<EHRule> *_offsets, std::vector<std::bitset<B>> *_chunks, SetElement* _offssetsIt, BitsetVector::iterator* _chunksIt, int _indInBitset)
Is it allowed to use template value inside a nested class?
If not, is there some other error I am making?

Answer 1

You need to use typename keyword for depended types. Here for example
typename BitsetVector::iterator* _chunksIt
//^^^^^^
Secondly, there is no typename needed for the template type alias
typedef std::vector<std::bitset<B>> BitsetVector;
// or better use
// using BitsetVector = std::vector<std::bitset<B>>;
The minimal example for the above have considered as follows:
#include <vector>
#include <iterator>
#include <bitset>
template <int B>
class SparseBitvector
{
typedef std::vector<std::bitset<B>> BitsetVector;
public:
class iterator : public std::iterator<std::input_iterator_tag, BitsetVector>
{
public:
explicit iterator(std::input_iterator_tag, BitsetVector, typename BitsetVector::iterator* _chunksIt)
{
}
};
};