The terminology is a bit weird: Positive vs. negative means presenting a stimulus vs. removing it. Reinforcement means increasing the frequency of a reaction and punishment means decreasing it. You have to logically conclude, whether the presented or removed stimulus is nice or unpleasant. Here is an overview:

    positive reinforcement:  presenting nice stimulus to increase frequency of behavior
    negative reinforcement:  removing unpleasant stimulus to increase frequency of behavior
    positive punishment:  presenting unpleasant stimulus to decrease frequency of behavior
    negative punishment:  removing nice stimulus to decrease frequency of behavior

The great confusion stems from the fact that in common English language, with punishment we mean both increasing good behavior and reducing bad behavior, whilst in classical conditioning terms, punishment always refers to reducing the frequency of a certain behavior.