Java Reference
In-Depth Information
Display 4.13
A Class with Constructors
(part 1 of 5)
This is our final definition of a class
whose objects are dates.
1
import
java.util.Scanner;
2
public
class
Date
3{
4
private
String month;
5
private
int
day;
6
private
int
year; //a four digit number.
7
public
Date()
No-argument constructor
8
{
9
month = "January";
10
day = 1;
11
year = 1000;
12
}
13
public
Date(
int
monthInt,
int
day,
int
year)
14
{
You can invoke another
method inside a
constructor definition.
15
setDate
(monthInt, day, year);
16
}
17
public
Date(String monthString,
int
day,
int
year)
18
{
19
setDate
(monthString, day, year);
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}
21
public
Date(
int
year)
22
{
A constructor usually initializes all
instance variables, even if there is not a
corresponding parameter.
23
setDate
(1, 1, year);
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}
25
public
Date(Date aDate)
26
{
27
if
(aDate ==
null
)//Not a real date.
We will have more to
say about this
constructor in
Chapter 5. Although
you have had enough
material to use this
constructor, you need
not worry about it
until Section 5.3 of
Chapter 5.
28
{
29
System.out.println("Fatal Error.");
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System.exit(0);
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}
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month = aDate.month;
33
day = aDate.day;
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year = aDate.year;
35
}
(continued)
