Java Reference
In-Depth Information
Although it may seem that we have lost sight of the fact, all these method definitions
must be inside of some class definition. Java does not have any stand-alone methods
that are not in any class. Display 4.2 rewrites the class given in Display 4.1 but this
time we have added a more diverse set of methods. Display 4.3 contains a sample
program that illustrates how the methods of the class in Display 4.2 are used.
TIP: Any Method Can Be Used as a void Method
A method that returns a value can also perform some action besides returning a value.
If you want that action, but do not need the returned value, you can invoke the
method as if it were a void method and the returned value will simply be discarded.
For example, the following contains two invocations of the method nextLine() ,
which returns a value of type String . Both are legal.
Scanner keyboard = new Scanner(System.in);
. . .
String inputString = keyboard.nextLine();
. . .
System.out.println("Press Enter to continue with program.");
keyboard.nextLine(); //Reads a line and discards it.
Display 4.2
A Class with More Methods (part 1 of 2)
The significance of the modifier private
is discussed in the subsection “ public
and private Modifiers” in Section 4.2
a bit later in this chapter.
1 import java.util.Scanner;
2 public class DateSecondTry
3 {
4 private String month;
5 private int day;
6 private int year; //a four digit number.
7 public void writeOutput()
8 {
9 System.out.println(month + " " + day + ", " + year);
10
}
11
public void readInput()
12
{
13
Scanner keyboard = new Scanner(System.in);
14
System.out.println("Enter month, day, and year.");
15
System.out.println("Do not use a comma.");
16
month = keyboard.next();
17
day = keyboard.nextInt();
18
year = keyboard.nextInt();
19
}
 
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