|Objects and Classes|
You are supposed to know the difference between a class and an object. This difference is explained on this page.
Classes are written and described in source programs
Objects are created and exist while programs are running
All objects cease to exist when the program execution terminates.
This is in conflict with the behavior of corresponding real-life phenomena, and it causes a lot of problems and challenges in many programs
Read more about classes vs. objects in the text book version of this material.