I/O Streams

Recall, from chapter 10, that input and output are done with streams of data. There is a standard input stream and a standard output stream.

When a Scanner object is constructed with System.in , it scans the standard input stream of characters for patterns that the program asks for and (sometimes) converts those characters to a specific data type. For example, the nextInt() method is used to match characters that can be converted to an int.