java学习55天2020/8/30

设计一款电子钟类，用于显示时、分、秒

• 含有形参有默认值的默认构造函数；

• 前缀++ 和 后缀—用于调整时间，每次调整均对秒进行调整，若秒满60，则分加1，若分满60则时加1，时满24，则清零重新开始；

• 设置函数用于输入（设定）时间；

• 设置函数用于输出时间。

  import java.util.Scanner;
  public class Time {
       private int hour;
       private int minute;
       private int second;
       public Time() {
           this.hour = 0;
          this.minute = 0;
           this.second = 0;
       }
       public Time(int hour, int minute, int second) {
           this.hour = hour;
           this.minute = minute;
           this.second = second;
       }
       public void zheng() {
           ++second;
           if (second >= 60) {
               second = 0;
               ++minute;
               if (minute >= 60) {
                   minute = 0;
                   ++hour;
                   hour %= 24;
               }
           }
       }
  
       public void dao() {
           second--;
           if (second < 0) {
               minute--;
               second = 59;
           }
           if (minute < 0) {
               minute = 59;
               hour--;
           }
           if (hour < 0) {
               hour = 23;
           }
       }
       public void input() {
           Scanner in = new Scanner(System.in);
           hour = in.nextInt();
           minute = in.nextInt();
           second = in.nextInt();
       }
       // 输出电子钟
       public void output() {
           System.out.println(hour + ":" + minute + ":" + second);
       }
       public boolean dengYu(Time t) {
           if (hour == t.hour && minute == t.minute && second == t.second) {
               return true;
           } else {
               return false;
           }
       }
       public static void main(String[] args) throws InterruptedException {
           int n;
           Scanner in = new Scanner(System.in);
           System.out.println("功能选择：");
           System.out.println("*********");
           System.out.println("1.钟表");
           System.out.println("2.正计时");
           System.out.println("3.倒计时");
           System.out.println("*********");
           System.out.print("请输入你的选择：");
           n = in.nextInt();
           if (n == 1) {
               System.out.print("请先校准时间：");
               Time t = new Time();
               t.input();
               while (true) {
                   t.output();t.zheng();
                   Thread.sleep(2000);
               }
           }
           if (n == 2) {
              Time t = new Time();
               while (true) {
                   t.output();
                   t.zheng();
                   Thread.sleep(2000);
               }
           }
           if (n == 3) {
               Time t1 = new Time();
               Time t2 = new Time();
               System.out.print("请输入时间：");
               t1.input();
               while (true) {
                  t1.output();
                   t1.dao();
                   Thread.sleep(2000);
                  if (t1.dengYu(t2)) {
                       break;
                   }
               }
               System.out.println("STOP!");
           }
       }
   }
  

   三，例题