playing with unordered buckets in c++

unordered_map_bucket.cpp

int main(int argc, char const *argv[])
{
	std::unordered_map<std::string, std::string> fooMap;
	const std::string s1 = "foobar";
	const std::string s2 = "doobar";
	const std::string s3 = "loobar";
	const std::string s4 = "4oobar";
	const std::string s5 = "77oobar";

	std::printf("Bucket count is %zu\n", fooMap.bucket_count());
	fooMap.insert(std::make_pair(s1, s2));
	fooMap.insert(std::make_pair(s3, s2));
	fooMap.insert(std::make_pair(s4, s2));
	fooMap.insert(std::make_pair(s5, s2));

	std::printf("Bucket count is %zu\n", fooMap.bucket_count());
	std::printf("%s is in bucket %zu\n", s1.c_str(), fooMap.bucket(s1));
	std::printf("%s is in bucket %zu\n", s2.c_str(), fooMap.bucket(s2));
	std::printf("%s is in bucket %zu\n", s3.c_str(), fooMap.bucket(s3));
	std::printf("%s is in bucket %zu\n", s4.c_str(), fooMap.bucket(s4));
	std::printf("%s is in bucket %zu\n", s5.c_str(), fooMap.bucket(s5));

	fooMap.rehash(30);
	std::printf("Bucket count is %zu\n", fooMap.bucket_count());
	std::printf("%s is in bucket %zu\n", s1.c_str(), fooMap.bucket(s1));
	std::printf("%s is in bucket %zu\n", s2.c_str(), fooMap.bucket(s2));
	std::printf("%s is in bucket %zu\n", s3.c_str(), fooMap.bucket(s3));
	std::printf("%s is in bucket %zu\n", s4.c_str(), fooMap.bucket(s4));
	std::printf("%s is in bucket %zu\n", s5.c_str(), fooMap.bucket(s5));

	std::printf("hash of %s in bucket is %zu\n", s1.c_str(), fooMap.hash_function()(s1)% fooMap.bucket_count());
	std::printf("hash of %s in bucket is %zu\n", s2.c_str(), fooMap.hash_function()(s2) % fooMap.bucket_count());
	std::printf("hash of %s in bucket is %zu\n", s3.c_str(), fooMap.hash_function()(s3)% fooMap.bucket_count());
	std::printf("hash of %s in bucket is %zu\n", s4.c_str(), fooMap.hash_function()(s4)% fooMap.bucket_count());
	std::printf("hash of %s in bucket is %zu\n", s5.c_str(), fooMap.hash_function()(s5)% fooMap.bucket_count());

	// iteration through hash map in order of buckets
	for (size_t i = 0; i < fooMap.bucket_count(); ++i)
	{
		std::printf("bucket %zu -----\n", i);
		for (auto elem = fooMap.begin(i); elem != fooMap.end(i); ++elem)
		{
			std::printf("Key : %s Val : %s\n", elem->first.c_str(), elem->second.c_str());
		}
	}
	return 0;
}