Given a date, you have to print the day of the week.
Examples:
Input : 2018 3 26 Output : Mon Input : 2010 8 9 Output : Wed
The idea is to use java built-in API Gregorian Calendar.
GregorianCalendar is a concrete subclass of Calendar and provides
the standard calendar system used by most of the world.
GregorianCalendar(int year, int month, int dayOfMonth) constructs a
GregorianCalendar with the given date set in the default time zone
with the default locale.
Several conditions are created to check the validity of
the input data. If an input is found to be wrong an Invalid
message will be printed as output.
// Necessary imports for using Gregorian Calendarimport java.util.Calendar;import java.util.GregorianCalendar;  class GFG {    static int method(int year, int month, int day)    {        // to check the validity of day of month        int[] darr = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };          // check validity of year and month        if (year > 0 && (month > 0 && month <= 12)) {              // check for a leap year and month of February              if ((year % 4 == 0 || year % 400 == 0) &&                 month == 2 && (day > 0 && day <= 29)) {                  // month starts at zero, so we need to put ( month - 1 ).                Calendar calendar = new GregorianCalendar(year, month - 1, day);                return calendar.get(Calendar.DAY_OF_WEEK);            }            else {                  // check the range of day of month                if (day > 0 && day <= darr[month - 1]) {                      // month starts at zero, so we need to put ( month - 1 ).                    Calendar calendar = new GregorianCalendar(year, month - 1, day);                    return calendar.get(Calendar.DAY_OF_WEEK);                }                else                    return 0;            }        }        else            return 0;    }    public static void main(String[] args)    {        String[] dayofweek = { "Invalid", "Sun", "Mon", "Tue",                                "Wed", "Thur", "Fri", "Sat" };        int y = 2018, m = 3, d = 26;        System.out.println(dayofweek[method(y, m, d)]);    }} |
Output:
Mon
