DayOfTheWeek.java

import java.util.Scanner;

public class DayOfTheWeek{
	public static void main(String[] args){
		Scanner input = new Scanner(System.in);

		System.out.print("Enter year: (e.g., 2021): ");
		int year = input.nextInt();
		System.out.print("Enter month: 1-12: ");
		int m = input.nextInt();
		if (m == 1 || m == 2){
			m += 12;
			year -= 1;
		}
		System.out.print("Enter the day of the month: 1-31: ");
		int q = input.nextInt();
		int j = year / 100;
		int k = year % 100;
		int h = (q + 26 * (m + 1) / 10 + k + k / 4 + j / 4 + 5 * j) % 7;
		System.out.print("Day of the week is ");
		switch (h){
			case 0: System.out.println("Saturday."); break;
			case 1: System.out.println("Sunday."); break;
			case 2: System.out.println("Monday."); break;
			case 3: System.out.println("Tuesday."); break;
			case 4: System.out.println("Wednesday."); break;
			case 5: System.out.println("Thursday."); break;
			case 6: System.out.println("Friday."); break;
		}
	}
}