new issue

Hi!

I am a newbie of learning levelDB, yet I followed the document to write a test code, it could't run, the detailed code is:
#include
#include
#include

int main(void)
{
leveldb::DB *db = nullptr;
leveldb::Options options;
options.create_if_missing = true;
leveldb::Status status = leveldb::DB::Open(options, "/tmp/testdb", &db);
assert(status.ok());

std::string key = "A";
std::string value = "a";
std::string get_value;

leveldb::Status s = db->Put(leveldb::WriteOptions(), key, value);

if (s.ok())
s = db->Get(leveldb::ReadOptions(), "A", &get_value);

if (s.ok())
std::cout << get_value << std::endl;
else
std::cout << s.ToString() << std::endl;

delete db;

return 0;
}