Driver Station I/O in C++

[AndrewD]

Hello all,
I'm trying to read buttons from the cypress board to fire relays on the 'bot.
My code so far (just for the relays and dsio) is:

class RobotDemo : public SimpleRobot
{
     Relay barrel1;
     Relay barrel2;
     Relay barrel3;
     DriverStation ds;

public:
     RobotDemo(void):
          barrel1(3),
          barrel2(4),
          barrel3(5),
          ds()
     {
           GetWatchdog().SetExpiration(0.1);
     }
     void OperatorControl(void)
     {
          GetWatchdog.SetEnabled(true);
          while (IsOperatorControl())
          {
               GetWatchdog().Feed();
               if (ds.GetDigitalIn(3)) {
                    barrel1.Set(Relay::kOn)
               } else {
                    barrel1.Set(Relay::kOff)
               }
          }
     }
}

of course there is more code for the drive train but this is all that needs help. i need to know what to put in the parentheses for "ds()" under "RobotDemo(void):"

Thanks in advance,
Andrew D.