..
Scanner scanner = new Scanner(System.in);
// Obtain input
System.out.print("Enter balance: ");
double balance = scanner.nextDouble();
...
The Scanner class has many methods, and you should consult the Java API documentation to see what
they are, and what choices you have.
You can also use a Scanner to read from a file. To associate a Scanner with a file of text, just pass
a FileReader object to the Scanner constructor:
sc = new Scanner(new FileReader( myFile.txt ) );
To read lines of text, you can use the nextLine() method of Scanner to transfer a line of text
into a String variable. You can also use the hasNextLine() method to test to see whether there is
something to read. Here??™s a snippet of code to loop, reading text for processing into a String called
lineOfData.
CHAP. 5] PROGRAMMING IN JAVA 91
String lineOfData;
Scanner sc = new Scanner( myFile.txt );
while( sc.hasNextLine() ) {
lineOfData = sc.nextLine();
...
}//while
When the program reaches the EOF, the hasNextLine() method will return false, and the program will
exit the while loop.
PRINTWRITER
The PrintWriter is another very convenient I/O class; it makes writing text to a file as easy as writing
text to the display. To create a PrintWriter that is associated with a file, you simply pass the name of the
file to the constructor.
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