[mikets]

Sure, how about this? It is basically the same as your Posedge_toggle class except that it allows the update method to also return the switch state so you don't have to make the get call.

class ToggleSwitch
{
private:
    bool switchValue;
    bool prevInput;

public:
    ToggleSwitch(void)
        : switchValue(false)
        , prevInput(false)
    {
    }

    bool GetSwitchValue(void)
    {
        return switchValue;
    }

    bool UpdateSwitchValue(bool currInput)
    {
        if (currInput != prevInput)
        {
            if (currInput)
            {
                switchValue = !switchValue;
            }

            prevInput = currInput;
        }

        return switchValue;
    }
};

...
...
ToggleSwitch tankMode;

while (IsOperatorControl())
{
    //
    // Check for button 6 press.
    //
    if (tankMode.UpdateSwitchValue(secondaryController->GetRawButton(6)))
    {
        //
        // Do tank drive.
        //
    }
    else
    {
        //
        // Do arcade drive.
        //
    }
    wait(0.02);
}