package math;

/**

* Find the day of the week for a given date.

*

* Link: http://www.geeksforgeeks.org/find-day-of-the-week-for-a-given-date/

*

* @author shivam.maharshi

*/

public class FindDayOfWeek {

public static int getDay(int d, int m, int y) {

int offset = 0;

//int[] month = new int[] { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };

int[] moffset = new int[] { 0, 3, 3, 6, 1, 4, 6, 2, 5, 0, 3, 5 };

int[] mloffset = new int[] { 0, 3, 4, 0, 2, 5, 0, 3, 6, 1, 4, 6 };

offset += d-1 + y - 2000 + getLeapYears(2000, y);

if (isLeapYear(y)) {

offset += mloffset[m];

} else {

offset += moffset[m];

}

// If this is 0, then it is Saturday.

return offset%7;

}

public static void main(String[] args) {

// 04-June-2016 is a Saturday.

System.out.println(getDay(4, 5, 2016));

}

public static int getLeapYears(int p, int c) {

int l = 0;

for (int i = p; i < c; i++) {

if (isLeapYear(i))

l++;

}

return l;

}

public static boolean isLeapYear(int y) {

return (y % 4 == 0 && y % 100 != 0) || ( y % 400 == 0);

}

}