题:编写一个小应用程序求100以内的全部素数.import java.awt.Graphics;
import java.applet.Applet; 
public class Test2{
         int n,j;       
         int y=100;
         int a[]=new int[30];        public void init()
        {   int i=2;
            for(j=0;j<30;j++) a[j]=0;
            for(j=0,n=2;n<=100;n++)
             {  
               while(n%i!=0) i++;
                if(i==n)
                {  
                    i=2 ; 
                    a[j]=n;
                    j++;
                } 
                     
             }
        }
        public void paint( Graphics g)
       {
         for(j=0;j<20;j++) 
           {y+=100; g.drawString(a[j]+"是素数",0,y);}
       }}
结果总是没初始化
我对在循环里怎么paint还不懂