#include <string>
#include <iostream>
using namespace std;
string getDateTime()
{
char txt[256];
int year, month, day;
// ....
// get system date time
// ...
sprintf(txt, "%04d-%02d-%02d", year, month, day);
return string(txt);
}
int _tmain(int argc, _TCHAR* argv[])
{
cout << getDateTime().c_str() << endl;

return 0;
}