Java Reference
In-Depth Information
Although it may seem that we have lost sight of the fact, all these method defini-
tions must be inside of some class definition. Java does not have any stand-alone meth-
ods 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 pro-
gram 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 dis-
carded. 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();
