Java演習(4) -- 変数と型 --

Transcription

1

2 (20, 20) O x (reserved y

3 (20, 20) (1)(Blocks1.java) import javax.swing.japplet; import java.awt.graphics; (reserved public class Blocks1 extends JApplet { public void paint(graphics g){ g.drawrect( 20, 20, 50, 20); g.drawrect( 90, 20, 50, 20); g.drawrect(160, 20, 50, 20); g.drawrect(230, 20, 50, 20); g.drawrect(300, 20, 50, 20); 10 } }

4 (20, 20) (reserved

5 (variable) (type) (reserved

6 Blocks2.java import javax.swing.japplet; import java.awt.graphics; public class Blocks2 extends JApplet { public void paint(graphics g){ int w = 50, h = 20, x = 20, y = 20, space = 20; g.drawrect(x, y, w, h); x = x + w + space; 10 g.drawrect(x, y, w, h); (reserved } } x = x + w + space; g.drawrect(x, y, w, h); x = x + w + space; g.drawrect(x, y, w, h); x = x + w + space; g.drawrect(x, y, w, h); 20

7 int() (e.g. -20, 10) float, double() (e.g , 3.4) ; (e.g. int x;),,...; (e.g. int x, y, z;) () = ; (e.g. x = 3;, x = a + b;) (reserved

8 int() 1, 12, -50 float, double 1.23, () char() a, x, Z boolean( ) true false (reserved

9 boolean true false byte 8bit short 16bit int 32bit ( ) long 64bit ( ) char 16bit Unicode float 32bit double 64bit (reserved

10 (declaration) ; int a;,,... ; double avg1, val x; (reserved

11 ( ) camel case() = ; =... (assignment) (reserved

12 (reserved () abstract boolean break byte case catch char class const continue default do double else extends final finally float for goto if implements import instanceof int interface long native new package private protected public return short static super switch synchronized this throw throws transient try void volatile while (reserved

13 (20, 20) (reserved

14 gif a (10, 10) a ( web (reserved

15 ImagePut.java (1)(ImagePut.java) import javax.swing.japplet; import javax.swing.imageicon; import java.awt.graphics; public class ImagePut extends JApplet { ImageIcon icon; (reserved public void init(){ icon = new ImageIcon(getImage(getCodeBase(), "den1s.gif")); } 10 } public void paint(graphics g) { icon.painticon(this, g, 10, 10); }

16 ImagePut.java 2 java.swing ImageIcon 6 ImageIcon icon ImagePut (reserved ()

17 ImagePut.java 9 getcodebase applet URL URL rocky/imageput.html applet URL rocky/ Image getimage(url url, String name) URL name ImageIcon(Image image) Image ImageIcon (reserved 12 painticon(component c, Graphics g, int x, int y) Component: applet (this) Graphics: (x, y):

18 ImagePut.java 8 init applet (reserved

19 gif (10, 10) (reserved

20 ImagePutBox.java (2)(ImagePutBox.java) import javax.swing.japplet; import javax.swing.imageicon; import java.awt.graphics; public class ImagePutBox extends JApplet { ImageIcon icon; int w, h; public void init(){ icon = new ImageIcon(getImage(getCodeBase(), "den1s.gif")); 10 w = icon.geticonwidth(); h = icon.geticonheight(); } (reserved } public void paint(graphics g) { icon.painticon(this, g, 10, 10); g.drawrect(10, 10, w, h); }

21 ImagePutBox.java 7 (w) (h) 11, 12 geticonwidth geticonheight icon (reserved

22 gif 5 (reserved