Question

Need help implementing this Java class

(Science: day of the week) Zeller's congruence is an algorithm developed by Christian Zeller to calculate the day of the week. The formula is h = (q + (26 * (m + 1)) / 10 + k + k / 4 + j / 4 + 5 * j) % 7 where

h is the day of the week (0: Saturday, 1: Sunday, 2: Monday, 3: Tuesday, 4: Wednesday, 5: Thursday, 6: Friday).

q is the day of the month.

m is the month (3: March, 4: April, ..., 12: December). January and February are counted as months 13 and 14 of the previous year.

j is the century (i.e., year/100).

k is the year of the century (i.e., year%100).

Note that the division in the formula performs an integer division. Write a program that prompts the user to enter a year, month, and day of the month, and displays the name of the day of the week. Here are some sample runs:

Enter year (e.g., 2012): 2015
Enter month (1-12): 1
Enter the day of the month (1-31): 25
Day of the week is Sunday!

and

Enter year (e.g., 2012): 2012
Enter month (1-12): 5
Enter the day of the month (1-31): 12
Day of the week is Saturday!

Answer 1

import java.util.*;
import java.util.Scanner;

public class Algo{

public static void main(String[] args){

Scanner sc = new Scanner(System.in);
int year,month,day;
System.out.print("Enter year (e.g., 2012):");
year = sc.nextInt();
System.out.print("Enter month (1-12):");
month = sc.nextInt();
System.out.print("Enter the day of the month (1-31):");
day = sc.nextInt();
int h,q,m,k,j;
q = day;
m = month;
j = year/100;
k = year%100;
h = (q+(26*(m+1))/10 + k+(k/4)+(j/4)+(5*j))%7;
String day_st = new String();
switch(h){

case 0:

   day_st = "Saturday!";
   break;
case 1:

   day_st = "Sunday!";
   break;
case 2:

   day_st = "Monday";
   break;
case 3:

   day_st = "Tuesday!";
   break;
case 4:

   day_st = "Wednesday";
   break;
case 5:

   day_st = "Thursday!";
   break;
case 6:

   day_st = "Friday!";
   break;
default:
   break;
}
System.out.println("Day of the week is "+ day_st);
}
}