So far, every example in this book has processed data that resided inside the program listing or came from the keyboard. You assigned constants and variables to other variables and created new data values from expressions. The programs also received input with scanf(), gets(), and the character input functions. With the large volumes of data that most real-world applications need to process, however, you need a better way of storing that data. For all but the smallest computer programs, disk files offer the solution.
After storing data on the disk, the computer helps you enter, find, change, and delete the data. The computer and C are simply tools to help you manage and process data. This chapter focuses on disk and file processing concepts.
