ex4_18.java

判断三角形

//4.18（显示当前日期和时间）
import javax.swing.JOptionPane;
public class Ex4_18{
   public static void main (String[] args) {
      long totalMilliseconds=System.currentTimeMillis();//获得从1970.1.1零点到此刻的毫秒数
      long totalSeconds=totalMilliseconds/1000;//获得从1970.1.1零点到此刻的秒数
      long totalMinutes=totalSeconds/60;
      long totalHours=totalMinutes/60;
      long totalDays=totalHours/24;
      int currentSecond=(int)(totalSeconds%60);
      int currentMinute=(int)(totalMinutes%60);
      int currentHour=(int)(totalHours%24)+8;//得到的CMT时间加上8小时为北京时间
      int currentYear=1970,currentMonth=1,currentDay,total=0,i=0;
      while(total<=totalDays){//从1970开始累加每年的天数，利用currentYear计算累加的次数即可得到现在的年份
         if(isLeapYear(currentYear))
         	total=total+366;
         else
         	total=total+365;
         currentYear++;
      };
      currentYear--;
      if(isLeapYear(currentYear)) total=total-366;
      else total=total-365;
      while(i<=totalDays-total){//同求年份一样，从一月份开始累加求得当前的月份
         i=i+getDayofMonth(currentMonth,currentYear);
         currentMonth++;
      }
      currentMonth--;
      currentDay=((int)totalDays-total)-(i-getDayofMonth(currentMonth,currentYear))+1;//求得当前的天数
      String printTime="当前时间为："+currentYear+"/"+currentMonth+"/"+currentDay+"  "+
      	             currentHour+":"+currentMinute+":"+currentSecond+"（北京时间）";
      JOptionPane.showMessageDialog(null,printTime);
      System.exit(0);
   }
   static boolean isLeapYear(int year){//判断是否为闰年的函数
      return year%400==0||(year%4==0&&year%100!=0);
   }
   static int getDayofMonth(int currentMonth,int currentYear){ //确定每个月的天数
     if(currentMonth==1||currentMonth==3||currentMonth==5||currentMonth==7||
        currentMonth==8||currentMonth==10||currentMonth==12)
        return 31;
     if(currentMonth==4||currentMonth==6||currentMonth==9||currentMonth==11)
         return 30;
     if(currentMonth==2) return isLeapYear(currentYear)? 29 : 28;
    return 0;
   }
}