C / C++ / MFC

class CSQLServerConnection;

class CSQLDocument
{
  ....
private:
  CSQLServerConnection* m_DatabaseConnection;
};

CSQLDocument::CSQLDocument()
{
   m_DatabaseConnection = new CSQLServerConnection;
}

#include "stdafx.h"
#include "SQLServerConnection.h"

#ifdef _DEBUG
#undef THIS_FILE
static char THIS_FILE[]=__FILE__;
#define new DEBUG_NEW
#endif

//////////////////////////////////////////////////////////////////////
// Konstruktion/Destruktion
//////////////////////////////////////////////////////////////////////

CSQLServerConnection::CSQLServerConnection()
{

}

CSQLServerConnection::~CSQLServerConnection()
{

}

bool CSQLServerConnection::Connect(string database, string host, string user, string password)
{
	server_connection = new Connection(database.c_str(), host.c_str(), user.c_str(), password.c_str());
	return true;
}

bool CSQLServerConnection::SQLQuery(string query, string& error_message)
{
	try
	{
		Query thequery = server_connection->query();
		thequery << query;
	}
	catch (BadQuery error)
	{
		error_message = error.error;
		return false;
	}
	return true;
}

//
//////////////////////////////////////////////////////////////////////

#if !defined(AFX_SQLSERVERCONNECTION_H__72EDA6F0_B4A2_4B36_8353_222CCFB751AB__INCLUDED_)
#define AFX_SQLSERVERCONNECTION_H__72EDA6F0_B4A2_4B36_8353_222CCFB751AB__INCLUDED_

#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000

#include <string>
#include <mysql++>

using namespace std;

class CSQLServerConnection  
{
public:
	CSQLServerConnection();
	virtual ~CSQLServerConnection();

	bool Connect(string database, string host, string user, string password);
	bool SQLQuery(string query, string& error_message);

private:
	string database_name;
	string user_name;
	string query_text;
	Connection* server_connection;
	Result query_result;
};

#endif // !defined(AFX_SQLSERVERCONNECTION_H__72EDA6F0_B4A2_4B36_8353_222CCFB751AB__INCLUDED_)

class SQLDocument
{
.....
private:   CSQLServerConnection* m_DatabaseConnection;
};

#include "SQLDocument.h"
#include "SQLServerConnection.h"
<p>
SQLDocument::SQLDOcument()
{
  m_DatabaseConnection = new CSQLServerConnection;
}

#include "SQLServerConnection.h"
#include "SQLDocument.h"

int nNrOfSamples = 10000;
float fSampling = .00000001923;
float t[ 10000 ];

// not sure about
// y(1:nr_of_samples) = y_long(1:nr_of_samples);

for( int i = 0; i < nNrOfSamples; i++ ) 
  t[ i ] = fSampling * i;