How to connect to MySQL using C++

class MySQLCon
{
 MYSQLmysql;
public:
 int errornum;
 string errortext;
public:
 //Initialize MySQLCon();
 //Close the database~MySQLCon();
 //Connect to database bool OpenConn(const char* host,const char* username,const char* pwd,const char* dbName,unsigned port=0);
 void GetErrorText();//Get error text void Close();//Close database bool ExecuteSQL(const char* sql);//Use SQL statement, unable to receive data bool QureySQL(const char* sql, vector<vector<string>>& resultSet);//Use SQL statement and receive data (select statement)
};

MySQLCon::MySQLCon()
{
 if (mysql_library_init(0, nullptr, nullptr)) 
 {
 cout << "CAPI initialization failed" << std::endl;
 getchar();
 exit(1);
 }
 if (mysql_init(&mysql)==nullptr)
 {
 cout << "Failed to initialize database variables" << std::endl;
 getchar();
 exit(1);
 }
 if (mysql_options(&mysql, MYSQL_SET_CHARSET_NAME, "gbk"))
 {
 cout << "Failed to set connection options" << std::endl;
 getchar();
 exit(1);
 }
}

//The parameters are host, username, password, database name, port number bool MySQLCon::OpenConn(const char* host, const char* username, const char* pwd, const char* dbName, unsigned port)
{
 //Connect to the database if (mysql_real_connect(&mysql, host, username, pwd, dbName, port, nullptr, 0)==nullptr)
 {
 cout << "Failed to connect to MySQL server" << std::endl;
 //Get the error text GetErrorText();
 exit(1);
 return false;
 }
 return true;
 
}

void MySQLCon::GetErrorText()
{
 //Get the error code errornum = mysql_errno(&mysql);
 //Get the error text errortext = mysql_error(&mysql);
 //Print error code cout << "error num: " << errornum << std::endl;
 //Print error text cout << "error text: " << errortext << std::endl;
 getchar();
}

bool MySQLCon::ExecuteSQL(const char* sql)
{
 //Use SQL statement but cannot receive data if (mysql_real_query(&mysql, sql, strlen(sql)))
 {
 GetErrorText();
 return false;
 }
 return true;
}

bool MySQLCon::QureySQL(const char* sql, vector<vector<string>>& resultSet)
{
 //Use SQL statements and receive data into vector container if (mysql_real_query(&mysql, sql, strlen(sql)))
 {
 GetErrorText();
 return false;
 }
 //Create a MYSQL result set MYSQL_RES* result = mysql_store_result(&mysql);
 //Get the total number of rows and columns unsigned int rows = mysql_num_rows(result);
 unsigned int cols = mysql_num_fields(result);
 //Used to record a piece of data in the result set MYSQL_ROW row;
 while (row = mysql_fetch_row(result))
 {
 //Create a vector container to store the data in row vector<string> lineDate;
 for (int i = 0; i < cols; i++)
 {
 if (row[i])
 {
 //Store the data of each column in row into lineDate lineDate.push_back(row[i]);
 }
 else
 {
 lineDate.push_back("");
 }
 }
 //Store the entire line of data in resultSet resultSet.push_back(lineDate);
 }
 //Release the result setmysql_free_result(result);
 return true;
}

void MySQLCon::Close()
{
 mysql_close(&mysql);
}
MySQLCon::~MySQLCon()
{
 Close();
 mysql_library_end();
}

int main()
{
 MySQLCon c_apiconn;
 c_apiconn.OpenConn("127.0.0.1", "root", "136119", "fancy");
 string sql = "use fancy;"
 vector<vector<string>> data;
 c_apiconn.ExecuteSQL(sql.c_str());
 sql = "select * from fancy.info;";
 c_apiconn.QureySQL(sql.c_str(), data);
 for (int i = 0; i < data.size(); i++)
 {
 for (int j = 0; j < data[i].size(); j++)
 {
 cout << data[i][j] << "\t";
 }
 cout << endl;
 }
 return 0;
}