How to pass a pointer to vector of pointers?

This is a C++ version of a duplicate question. I know the pointers to vectors a bit much in the following, but I did this in order to duplicate a much larger project. The members of info_a are not properly printing from within print_b and I have been unable to properly pass the vector of pointers.

With what I have tried, the members of info_a are not properly printing from within print_b. The first element is fine, but the next two are not.

The structs and print_b are from a third-party api and I am trying to pass in what they are expecting.

Here's the working code ...

http://coliru.stacked-crooked.com/a/c3ad6af6da9409a5

Does anyone see where I am going wrong?

typedef struct {
    uint16_t a1;
    uint8_t a2;
    uint8_t a3;
} info_a;

typedef struct {
    uint16_t id;
    unsigned int arr_sz;
    info_a *arr;
} info_b;

void print_a(const info_a* a)
{
    using namespace std;

    cout <<
        "a->a1 0x" << hex << setfill('0') << setw(4) << a->a1 << std::endl <<  
        "a->a2 0x" << hex << setfill('0') << setw(2) << a->a2 << std::endl <<  
        "a->a3 0x" << hex << setfill('0') << setw(2) << a->a3 << std::endl;    
}

void print_b(const info_b* b)
{ 
    using namespace std;

    cout << "b->id 0x" << hex << setfill('0') << setw(4) << b->id << endl      
        << "b->arr_sz " << hex << setfill('0') << setw(2) << b->arr_sz << endl;

    for (unsigned int i = 0; i < b->arr_sz; ++i) {                             
        const info_a *elem = &(b->arr[i]);                                     

        print_a(elem);
    }
}

int main(int argc, char **argv)
{
    std::shared_ptr<std::vector<std::shared_ptr<info_a>>> sp_info_a =
        std::make_shared<std::vector<std::shared_ptr<info_a>>>();              

    std::shared_ptr<std::vector<std::shared_ptr<info_b>>> sp_info_b =          
        std::make_shared<std::vector<std::shared_ptr<info_b>>>();              

    int offset = 0;

    for (uint16_t i = 1; i <= 1; ++i) {
        for (uint16_t j = 1; j <= 3; ++j) {                                    
            std::shared_ptr<info_a> a_info =                                   
                std::make_shared<info_a>(info_a { j, 0x31, 0x32 } );           

            sp_info_a->push_back(a_info);                                      
        }

        std::shared_ptr<info_b> b_info = std::make_shared<info_b>(             
            info_b {
                static_cast<uint16_t>(i),                                      
                static_cast<unsigned int>(sp_info_a->size()),                  
                (*sp_info_a)[offset].get()                                     
            });

        sp_info_b->push_back(b_info);

        print_b(b_info.get());

    }

    return 0;
}