【简答题】
阅读下列程序,请回答以下问题: import java.awt.*;import javax.swing.*;import java.awt..*; class MyPanel extends JPanel implements MouseListener{ int leftx,lefty,rightx,righty; boolean twoClick; MyPanel() { twoClick=false;addMouseListener(this); } public void mousePressed(Mouse e){ if(!twoClick){ leftx=e.getX();lefty=e.getY(); }else{ rightx=e.getX();righty=e.getY();repaint(); } twoClick=!twoClick; } public void mouseClicked(Mouse e){} public void mouseEntered(Mouse e){} public void mouseExited(Mouse e){} public void mouseReleased(Mouse e){} public void paintComponent(Graphics g){ g.clearRect(0,0,this.getWidth(),this.getHeight()); g.fillRect(1eftx,lefty,Math.abs(rightx-leftx), Math.abs(righty-lefty)); } } class MyWin extends JFrame{ MyPanel p=new MyPanel(); MyWin(){ getContentPane().add(p); setSize(400,400);setLocation(100,100);setVisible(true); } } public class Test35 extends JFrame{ public static void main(String[]args){new MyWin();} } 程序运行时,用户在界面的不同位置,用鼠标点击两次,界面中会出现什么
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参考解析:
举一反三