中间那段代码是什么意思作用是什么？

Question

import java.util.Scanner;

public class SmartDate {

private final int month;
private final int day;
private final int year;

public SmartDate(int m, int d, int y) {
    switch (m) {
    case 1:
    case 3:
    case 5:
    case 7:
    case 8:
    case 10:
    case 12:
        if (d > 0 && d <= 31) {
            month = m;
            day = d;
            year = y;
        } else {
            throw new IllegalArgumentException("Illegal date");
        }
        break;
    case 4:
    case 6:
    case 9:
    case 11:
        if (d > 0 && d <= 30) {
            month = m;
            day = d;
            year = y;
        } else {
            throw new IllegalArgumentException("Illegal date");
        }
        break;
    case 2:
        if (y % 4 == 0 && y % 100 != 0 || y % 400 == 0) {
            if (d > 0 && d <= 29) {
                month = m;
                day = d;
                year = y;
            } else {
                throw new IllegalArgumentException("Illegal date");
            }
        } else {
            if (d > 0 && d <= 28) {
                month = m;
                day = d;
                year = y;
            } else {
                throw new IllegalArgumentException("Illegal date");
            }
        }
        break;
    default:
        throw new IllegalArgumentException("Illegal date");
    }
}

public int month() {
    return month;
}

public int day() {
    return day;
}

public int year() {
    return year;
}

/**
 * Exercise 1.2.12
 * 
 * @return day of the week
 */
public String dayOfTheWeek() {
    // Zeller formula
    int month = this.month;
    int year = this.year;
    if (month <= 2) {
        month += 12;
        year--;
    }
    int week = (day + 2 * month + 3 * (month + 1) / 5 + year + year / 4 - year / 100 + year / 400) % 7;
    switch (week) {
    case 0:
        return "Monday";
    case 1:
        return "Tuesday";
    case 2:
        return "Wednesday";
    case 3:
        return "Thursday";
    case 4:
        return "Friday";
    case 5:
        return "Saturday";
    case 6:
        return "Sunday";
    default:
        return null;
    }
}


public String toString() {
    return month() + "/" + day() + "/" + year();
}

/*
public boolean equals(Object x) {
    if (this == x) {
        return true;
    }
    if (x == null) {
        return false;
    }
    if (this.getClass() != x.getClass()) {
        return false;
    }
    SmartDate that = (SmartDate) x;
    if (this.day != that.day) {
        return false;
    }
    if (this.month != that.month) {
        return false;
    }
    if (this.year != that.year) {
        return false;
    }
    return true;
}//这段代码的作用是什么？*/

public static void main(String[] args) {
    Scanner sc=new Scanner(System.in);
    int m = sc.nextInt();
    int d = sc.nextInt();
    int y = sc.nextInt();
    try {
        SmartDate date = new SmartDate(m, d, y);
        System.out.println(date);//？？
        System.out.println(date.dayOfTheWeek());//？？
    } catch (IllegalArgumentException e) {
        e.printStackTrace();
    }
}

}

Answer 1

不太清楚你具体问的是那一段代码，如果是dayOfTheWeek这个方法体中的，这里就是在通过一段自己设定的算法，通过获取到的天，月等时间计算出当天是星期几。具体的计算方式，就要思考一下了，
你的问题描述的不够清晰