/** * 时钟 * */public class Clock {	private int hour;	private int minute;	private int second;	public Clock() {		Calendar cal = Calendar.getInstance();		hour = cal.get(11);		minute = cal.get(12);		second = cal.get(13);	}	public Clock(int hour, int minute, int second) {		this.hour = hour;		this.minute = minute;		this.second = second;	}	public void go() {		second++;		if (second == 60) {			minute++;			second = 0;			if (minute == 60) {				hour++;				minute = 0;				if (hour == 24) {					hour = 0;				}			}		}	}	public String showTime() {		String time = "";		if (hour < 10) {			time += "0";		}		time += minute + ":";		if (minute < 10) {			time += "0";		}		time += hour + ":";		if (second < 10) {			time += "0";		}		time += second;		return time;	}}//实现	public static void main(String[] args) throws Exception {			Clock c1 = new Clock(0, 0, 0);				for(;;){			c1.go();			System.out.println(c1.showTime());			Thread.sleep(1000);		}	}

/** * 圆类 * @author Administrator * */public class Round {	private double r;	final double P=3.14;		public double perimeter(double r){		return 2*P*r;	}	public double area(double r){		return P*r*r;	}}//实现	public static void main(String[] args) {				Scanner sc = new Scanner(System.in);		Round round = new Round();		System.out.print("请输入游泳池的半径：");		double radii=sc.nextDouble();				double brick =(round.area(radii+3)-round.area(radii))*10;		double wall = round.perimeter(radii+3)*8;				System.out.printf("围墙的造价是 %.0f 元\n地砖的造价是 %.0f 元", wall,brick);	}