First, it is essential to understand that everything that runs on a computer is in memory. When we run a program, it is read from the disk, loaded into memory, and becomes the execution stream. When we read from a file on a disk, CD, or flash drive, it is firstread into memory and accessed from there, not from its original location (this is an oversimplification since there is a bit more that goes on). All of the functions we call and execute are in memory. All of the variables, structures, and arrays we declare are given their own locations in memory. Finally, all of the parts of the computer that we can read from or write to are accessible through some predefined memory location. How the OS handles all of the system devices, system resources (memory), and the filesystem is beyond the scope of this book.
Second, once we understand that everything is in memory, we must know that each byte of memory is addressable. The memory address...