A vital part of any program is the ability to hold information transiently or permanently. That is, the information can be held for the duration of a program or just for the length of time that it is needed.
Think back to Chapter 1, where we looked at a computer in terms of processing power and storage. Part of that storage—the bit that is emptied when you turn off the machine—is called memory. The information that you need to process during the lifecycle of a program is stored in memory.
Anything you might need once the program has finished needs to be put somewhere else—usually on the hard drive of the computer.
Within a program, you can allocate areas of computer memory to hold the information that you need. It might help to ...