public class DashLine

$\{$ public static void main$($String$[]$ args$)\{$new FrDashLine$()$;$\}$

$\}$

class FrDashLine extends Frame

$\{$ CvDashLine cv $=$ new CvDashLine$()$;

FrDashLine$()$

$\{$ super$("$Dashed lines"$)$;

addWindowListener

$($ new WindowAdapter$()$

$\{$ public void windowClosing$($WindowEvent e$)\{$System$.$exit$(0)$;$\}$

$\}$

$)$;

setSize$(500,300)$;

add$("$Center$",$ cv$)$;

setCursor$($Cursor$.$getPredefinedCursor$($Cursor$.$CROSSHAIR$\_$CURSOR$))$;

show$()$;

$\}$

$\}$

class CvDashLine extends Canvas

$\{$ int xA$,$ yA$,$ xB$,$ yB;

int np $=0$;

CvDashLine$()$

$\{$ addMouseListener

$($ new MouseAdapter$()$

$\{$ public void mousePressed$($MouseEvent evt$)$

$\{$ int X $=$ evt.getX$(),$ Y $=$ evt.getY$()$;

if $($np $==2)$ np $=0$;

np$++$;

if $($np $==1)\{$xA $=$ X; yA $=$ Y;$\}$ else $\{$xB $=$ X; yB $=$ Y;$\}$

repaint$()$;

$\}$

$\}$

$)$;

$\}$

public void paint$($Graphics g$)$

$\{$ if $($np $<2)$ return;

g$.$drawRect$($xA$,$ yA$,$ xB $-$ xA$,$ yB $-$ yA$)$;

int xP $=(3*$ xA $+$ xB$)/4,$ yP $=(3*$ yA $+$ yB$)/4,$

xQ $=($xA $+3*$ xB$)/4,$ yQ $=($yA $+3*$ yB$)/4$;

Lines.dashedLine$($g$,$ xP$,$ yP$,$ xQ$,$ yP$,20)$;

Lines.dashedLine$($g$,$ xQ$,$ yP$,$ xQ$,$ yQ$,20)$;

Lines.dashedLine$($g$,$ xQ$,$ yQ$,$ xP$,$ yQ$,20)$;

Lines.dashedLine$($g$,$ xP$,$ yQ$,$ xP$,$ yP$,20)$;

Lines.dashedLine$($g$,$ xA$,$ yA$,$ xP$,$ yP$,20)$;

Lines.dashedLine$($g$,$ xB$,$ yA$,$ xQ$,$ yP$,20)$;

Lines.dashedLine$($g$,$ xB$,$ yB$,$ xQ$,$ yQ$,20)$;

Lines.dashedLine$($g$,$ xA$,$ yB$,$ xP$,$ yQ$,20)$;

$\}$

$\}$

class Lines

$\{$ static void dashedLine$($Graphics g$,$ int xA$,$ int yA$,$ int xB$,$ int yB$,$

int dashLength$)$

$\{$ float u$1=$ xB $-$ xA$,$ u$2=$ yB $-$ yA$,$

L $=($float$)$Math$.$sqrt$($u$1*$ u$1+$ u$2*$ u$2)$;

int n $=$ Math.round$(($L$/$dashLength $+1)/2)$;

float h$1=$ u$1/(2*$ n $-1),$ h$2=$ u$2/(2*$ n $-1)$;

for $($int i$=0$; i