c++-C++连接mysql数据库时，用getString()方法总是出错

mysqlc++数据库

http://www.cnblogs.com/joeblackzqq/p/4332945.html
我按照上面这个链接的教程，用了第二种Connector C++的方法，配置好boost的路径和mysql的路径后，就修改了一下范例的代码：

<code> #include <iostream>#include <map>#include <string>#include <memory>#include "mysql_driver.h"#include "mysql_connection.h"#include "cppconn/driver.h"#include "cppconn/statement.h"#include "cppconn/prepared_statement.h"#include "cppconn/metadata.h"#include "cppconn/exception.h"using namespace std;using namespace sql;int main(){    sql::mysql::MySQL_Driver *driver = 0;    sql::Connection *conn = 0;    try    {        driver = sql::mysql::get_mysql_driver_instance();        conn = driver->connect("tcp://localhost:3306/tree", "root", "123");        cout createStatement();    stat->execute("set names 'gbk'");    ResultSet *res;    res = stat->executeQuery("SELECT * FROM testuser");    while (res->next())    {        cout getInt("id") getString("name") getString("address") </memory></string></map></iostream></code>

为此我创建了一个数据库tree和表testuser：

<code>create database tree;use tree;create table testuser(id INT(4) PRIMARY KEY,name CHAR(25),address varchar(45));desc testuser;insert into testuser values(1,'Tom','China Beijing'),(2,'Amy','America NewYork');select*from testuser;</code>

准备工作都做好了，然后就开始执行：
问题来了：