面向对象的第二次pta作业第二题：判断闰年及星期几

import java.util.Scanner;
public class Main {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner input = new Scanner(System.in);
        int year = input.nextInt();
        int month = input.nextInt();
        int day = input.nextInt();
        
        if(year>2020||year<1820||month>12||month<1||day<1||day>31) {
            System.out.println("Wrong Format");
            System.exit(0);
        }
        switch (month) {
        case 4:case 6:case 9:case 11:
            if (day>30) {
                System.out.println("Wrong Format");
                System.exit(0);
            }
            break;
        case 2:
            if (isLeapYear(year)&&day>29) {
                System.out.println("Wrong Format");
                System.exit(0);
            }
            if (day>28) {
                System.out.println("Wrong Format");
                System.exit(0);
            }
            break;
        }
        
        boolean l = isLeapYear(year);
        int days = numOfDays(year, month, day);
        String b = " not ";
        if(l)
            b = " ";
        
        System.out.println(year+" is"+b+"a leap year.");
        System.out.println(year+"-"+month+"-"+day+" is "+getWhatDay(days)+".");
    }
    
    public static boolean isLeapYear(int year) {//判断year是否为闰年，返回boolean类型；
        boolean y1 = year%4 == 0;
        boolean y2 = year%100 != 0;
        boolean y3 = year%400 == 0;
        
        if((y1&&y2)||y3)
            return true;
        else 
            return false;
    }
    
    public static int numOfDays(int year,int month ,int day) {//求出year-month-day到0001-1-1的距离天数，返回整型数；
        
        int arr[] = {0,31,28,31,30,31,30,31,31,30,31,30,31};
        int i,j,d = 0;
        for(i=1;i<year;i++) {
            d=d+365;
            if(isLeapYear(i)) 
                d++;
        }
        for(j=1;j<month;j++) 
            d=d+arr[j];
        d=d+day;
        if(isLeapYear(year)&&month>2)
            d++;
        return d;
    }
    public static String getWhatDay(int days) {//根据天数返回星期几，其中参数days为天数，整型数，返回星期几的英文单词。
        String whatDay = null;
        int s = days%7;
        switch (s) {
        case 1: whatDay = "Monday";break;
        case 2: whatDay = "Tuesday";break;
        case 3: whatDay = "Wednesday";break;
        case 4: whatDay = "Thursday";break;
        case 5: whatDay = "Friday";break;
        case 6: whatDay = "Saturday";break;
        case 0: whatDay = "Sunday";break;
        }
        return whatDay;
    }

}

 

 哎呀学c的时候我就不喜欢日期题啦 

达成新成就——boolean的用法~（好像很方便耶）