What Is the Difference Between a Contingent Being and a Necessary Being?

A contingent thing will be the kind of thing that has the potential not to exist. An example would be like a rock or a person. If there's any time at which it doesn't exist, then its nature is consistent with its non existence. All theories fall within those categories. Let me let me ask a question before lance jum said, how did you define the difference between a contingent being and a necessary being?