又一段不可征程编译的CODE,请多指教！

Question

loop_index你没声明
改为下：
import java.awt.*;
import java.awt.event.*;
import java.applet.Applet;   public class canvaser extends java.applet.Applet implements ActionListener {      int loop_index;
      Button button1;
      BoxCanvas boxcanvas;      public void init() {         add(button1=new Button("Move Rectangle"));
         button1.addActionListener(this);
        
         boxcanvas=new BoxCanvas();
         boxcanvas.resize(100,100);
         add(boxcanvas);        
 
     }      public void actionPerformed(ActionEvent event) {         if(event.getSource()==button1) {
            for(loop_index=0; loop_index<100; loop_index++) {
               boxcanvas.setLocation(loop_index,0);
     }    }   }
  
  }      class BoxCanvas extends java.awt.Canvas {         public void paint(Graphics g) {
         
            g.drawRect(10,50,40,40);      }    }  

Answer 1

int loop_index;for(loop_index=0; loop_index<100; loop_index++)                boxcanvas.setLocation(loop_index,0);这样就ok了。