segmentation fault ./main (no replies)

I'm Getting this error when it reaches the
"int rowcnt = res -> rowsCount();" line.

My c++ is a little rusty and I can figure it out. Any help would apprecisted.

#include <stdlib.h>
#include <iostream>
#include <sstream>
#include <stdexcept>
/* uncomment for applications that use vectors */
#include <vector>

#include "mysql_connection.h"

#include <cppconn/driver.h>
#include <cppconn/exception.h>
#include <cppconn/resultset.h>
#include <cppconn/statement.h>
#include <cppconn/prepared_statement.h>

#define EXAMPLE_HOST "localhost"
#define EXAMPLE_USER "worlduser"
#define EXAMPLE_PASS "worldpass"
#define EXAMPLE_DB "world"

using namespace std;


class cmysql{

public:
string host;
string user;
string pass;
string database;


vector<string> getdatacolumns(string strsql){
cout << "begin" << endl;
vector<string> verr;
cout << "Connector/C++ tutorial framework..." << endl;
cout << endl;

try {

vector<string> myreturn;
sql::Driver* driver = get_driver_instance();
std::auto_ptr<sql::Connection> con(driver->connect(host, user, pass));
con->setSchema(database);
std::auto_ptr<sql::Statement> stmt(con->createStatement());
stmt->executeQuery("select * from customer");
std::auto_ptr <sql::ResultSet> res;

do {

res.reset(stmt->getResultSet());
//Setup Vector

int rowcnt = res -> rowsCount();

vector<string> vec;

unsigned int i =1;

while (res->next()) {

vec = res->getString("last_name") + "," +res->getString("first_name") ;

i = i + 1;

}
return vec;
} while (stmt->getMoreResults());

//=================================================================================

}
catch (sql::SQLException &e) {
/*
MySQL Connector/C++ throws three different exceptions:

- sql::MethodNotImplementedException (derived from sql::SQLException)
- sql::InvalidArgumentException (derived from sql::SQLException)
- sql::SQLException (derived from std::runtime_error)
*/
cout << "# ERR: SQLException in " << __FILE__;
cout << "(" << __FUNCTION__ << ") on line " << __LINE__ << endl;
/* what() (derived from std::runtime_error) fetches error message */
cout << "# ERR: " << e.what();
cout << " (MySQL error code: " << e.getErrorCode();
cout << ", SQLState: " << e.getSQLState() << " )" << endl;
verr[0] = e.getSQLState();
//return EXIT_FAILURE;
}

}

};