Just as the program is about to close,
how many objects have been created
6 --- three Point objects and three temporary String objects
and how many object references are there? 3 --- each referencing a Point
Has any garbage been created? 3 objects --- each unreferenced String object
Look again at the description of 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.
A parameter is information you supply to a method.
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( "First values: " + pt ); pt.move( -13, 49 ) ; // change the x and y in the Point System.out.println( "Final values: " + pt ); } }
Here is what it writes to the screen:
First values: java.awt.Point[x=12,y=45] Final values: java.awt.Point[x=-13,y=49]