Isn't it disturbing, that you have to select the database driver interactively? To stop it change the first part of your code:
Example 3.1. Preselect the driver and user information
#define HAVE_SSTREAM 1
#include <hk_classes.h>
#include <iostream>
int main()
{
hk_drivermanager* mydrivermanager = new hk_drivermanager();
if (mydrivermanager==NULL) {cout <<"error creating mydrivermanager"<<endl;exit(1);}
hk_connection* myconnection = mydrivermanager->new_connection("mysql");
if (myconnection==NULL) {cout <<"error creating myconnection"<<endl;exit(1);}
myconnection->set_host("localhost");
myconnection->set_user("root");
myconnection->set_password("mypasswd");
myconnection->connect();
.
.
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