BHSawesome AP CSA

While we can initialize arrays and ArrayLists in our programs that’s only reasonable to do for small amounts of data. It’s not very convenient if we want to write a program that processes a lot of data. And processing large amounts of data is one of the things computers are great at. Also, if we initialize our data structures in our program, then we need to edit our program and recompile it if we want to process different data, which is not convenient at all.

Instead of embedding data directly in the source code of our programs, we typically store data as files on the computer’s hard drive and then load data from those files in our programs. This allows us to write a program once that can run the same computation on different data just by loading a different file.

In this chapter we’ll look at how to load data from files and put it into an ArrayList so we can then compute answers based on the data using list algorithms like the ones we discussed in the previous chapter.