And the answers come from procedures. Parameters and returned values Along with the call, the procedure might require some extra information, so it doesn't have to recompute things that other procedures might have already figured out. The LocateMouse procedure might need to be told where the mouse is. The location of the mouse is usually expressed in a coordinate system like the Cartesian plane that you learned about in high school. An x coordinate and a y coordinate.
Parameters are important for three reasons.
And second, the mouse may have moved in the time it took to call the LocateMouse procedure. And third, a procedure may be called to do some computation, for example, to look up a record in a database. Such a procedure would require a user's name or account number as a parameter, to identify the record that's to be looked up. It's the answer that the procedure sends back to the procedure that called it. A database-access procedure call might return a set of values, all the elements of the record indicated by the key identifier it received as a parameter.