[说明] 下面是一个Appkt程序,其功能是从3~100之间(包括3和100)每隔0.5秒显示一个新的数字,如果数字为素数,则显示为灰色,其他为绿色。 程序运行结果如图4所示。 import java. awt. * import java. applet. Applet < applet code = ex2_7, class width = 800 height = 400 > </applet >
public class ex2_7 extends Applet { public Color color2_7 = Color. black; private iht n2_7 = 3; public myPrime thPrime2_7; public void init( ) { thPrime2_7 = new myPrime(this); thPrime2_7, start( );}public void paint(Graphics g) { g, setColor( color2_7 ); g. drawString( (1) ,50,50);}public int getlnt( ) { return n2_7;}public void setlnt (int i) { n2_7 = i;}}class myPrime extends Thread Iex2_7 obj2_7;myPrime (ex2_7 o) { this. obj2_7 = o;} public boolean isPrime(int n){boolean bPrime = true;iht i =2;if( (2) ) return false;while( i < n - ]&&bPrime) { if( (3) ) bPrime = false; i++;}return bPrime;}public void run( ) { int i; for (i = 3; (4) ;i++) { if (isPrime(i) )obj2 _7, color2_7 = Color, gray; elseobj2_7, color2_7 = Color. green; (5) ;obj2_7, repaint( ); try {sleep(S00);} catch (InterruptedException ie) { } }} }ex2_7, html< HTML > < HEAD > <TITLE > ex2_7 </TITLE ></HEAD >< BODY ><appletcode =" ex2_, class" width =800 height =400 ></applet ></BODY ></HTML >