leapyear.java

Java程序设计实验与实训源代码经典的JAVA学习教材

import java.awt.*;
import java.applet.*;
import java.awt.event.*;


public class LeapYear extends Applet implements ActionListener{
	Label prompt;
	TextField input;
	Button btn;
	int year;
	boolean flag,leap;
	
	public void init() {
		prompt=new Label("请输入需要判断的年份：");
		input=new TextField(5);
		btn=new Button("判断");
		add(prompt);
		add(input);
		add(btn);
		btn.addActionListener(this);
	}

	public void paint(Graphics g) {
		if(flag)
		   if(leap)
		     g.drawString(year+"年是一个闰年",80,50);
		   else
		     g.drawString(year+"年不是一个闰年",80,50);
	}
	
	public void actionPerformed(ActionEvent e){
		year=Integer.parseInt(input.getText());
		
		if(year%4==0){
			if(year%100==0){
				if(year%400==0)
				   leap=true;
				else
				   leap=false;
		    }
		    else
		      leap=true;
		}
		else
		   leap=false;
		   
		flag=true;
		repaint(); 
	}
}