Just as the program is about to close, how many objects have been created ?
Six — threePoint
objects and three temporaryString
objects
How many object references are there?
Three — each referencing a Point
Has any garbage been created?
Three objects — each temporary String
object
Point
Look again at the description of class Point, class Point. One of the methods is:
public void move( int x, int y ) ;
This method is used to change the x and the y data inside a Point
object.
The modifier public
means that it can be used anywhere in your program;
void
means that it does not return a value.
This part of the description
( int x, int y )
says that when you use move
,
you need to supply two int
parameters that give the new location of the point.
Here is the example program, modified again:
import java.awt.*;
class PointEg4
{
public static void main ( String arg[] )
{
Point pt = new Point( 12, 45 ); // construct a Point
System.out.println( pt );
pt.move( -13, 49 ) ; // change the x and y in the Point
System.out.println( pt );
}
}
Here is what it writes to the screen:
java.awt.Point[x=12,y=45]
java.awt.Point[x=-13,y=49]
How many Point
objects are created by this program?
How many temporary String
objects are created by this program?