Write a java program to display the dates of before and after days for a given date.

Write a java program to display the dates of before and after days for a given date.

Program Code:

import java.io.*;

public class Date 

{

private final int month;

private final int day;

private final int year;

public Date(int m, int d, int y) 

{

if (!isValid(m, d, y))

throw new RuntimeException("Invalid");

month = m;

day = d;

year = y;

}

private static boolean isValid(int m, int d, int y) 

{

int[] DAYS = { 0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };

if (m < 1 || m > 12)

return false;

if (d < 1 || d > DAYS[m])

return false;

if (m == 2 && d == 29 && !isLeapYear(y))

return false;

return true;

}

private static boolean isLeapYear(int y) 

{

if (y % 400 == 0)

return true;

if (y % 100 == 0)

return false;

return (y % 4 == 0);

}

public Date next() 

{

if (isValid(month, day + 1, year))

return new Date(month, day + 1, year);

else if (isValid(month + 1, 1, year))

return new Date(month + 1, 1, year);

else

return new Date(1, 1, year + 1);

}

public boolean isAfter(Date b) 

{

return compareTo(b) > 0;

}

public boolean isBefore(Date b) 

{

return compareTo(b) < 0;

}

public int compareTo(Date b) 

{

if (year != b.year)

return year - b.year;

if (month != b.month)

return month - b.month;

return day - b.day;

}

public String toString() 

{

return day + "-" + month + "-" + year;

}

public static void main(String[] args) 

{

Date today = new Date(7, 12, 2010);

System.out.println(today);

Date nextDate = today.next();

System.out.println(nextDate);

System.out.println(today.isAfter(nextDate));

System.out.println(today.next().isAfter(today));

System.out.println(today.isBefore(nextDate));

System.out.println(nextDate.compareTo(today));

}

}