C++ vector ouroboros

ouroboros.cpp

#include <vector>

#include <stdint.h>
#include <inttypes.h>
#include <stdio.h>

int main(int argc, char **argv){
    (void)argc;
    (void)argv;

    std::vector<uint8_t> *b;
    {
        std::vector<uint8_t> a(sizeof(a));
        b = new(a.data()) std::vector<uint8_t>();
        std::swap(a, *b);
    }

    printf("b = %p\n", b);
    printf("b->size() = %zu\n", b->size());

    for(size_t i = 0; i < b->size(); i++){
        printf("(*b)[%zu] = %" PRIx8 "\n", i, (*b)[i]);
    }

    return 0;
}