Question

Use Java

(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 + 5j) % 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.

Sample Run 1

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

Sample Run 2

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

Sample Run 3

Enter year: (e.g., 2012): 2002
Enter month: 1-12: 3
Enter the day of the month: 1-31: 26
Day of the week is Tuesday

Sample Run 4

Enter year: (e.g., 2012): 2008
Enter month: 1-12: 1
Enter the day of the month: 1-31: 1
Day of the week is Tuesday

Sample Run 5

Enter year: (e.g., 2012): 2000
Enter month: 1-12: 2
Enter the day of the month: 1-31: 12
Day of the week is Saturday

(Hint: January and February are counted as 13 and 14 in the formula, so you need to convert the user input 1 to 13 and 2 to 14 for the month and change the year to the previous year.)

Class Name: Exercise03_21

If you get a logical or runtime error, please refer https://liveexample.pearsoncmg.com/faq.html.

Answer 1

Sol: Here is the java code with a sample output below.

// Java program to find Find the Day 
// for a Date 
import java.util.*; 

public class Main
{ 
        // Print Day for a Date 
        static void Zellercongruence(int day, int month, 
                                                                int year) 
        { 
                if (month == 1) 
                { 
                        month = 13; 
                        year--; 
                } 
                if (month == 2) 
                { 
                        month = 14; 
                        year--; 
                } 
                int q = day; 
                int m = month; 
                int k = year % 100; 
                int j = year / 100; 
                int h = q + 13*(m + 1) / 5 + k + k / 4 + j / 4 + 5 * j; 
                h = h % 7; 
                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; 
                } 
        } 
        
        // Driver code 
        public static void main(String[] args) 
        { 
                Scanner sc=new Scanner(System.in);
            System.out.println("Enter Year: (e.g., 2012): ");
            int year=sc.nextInt();
            System.out.println("Enter month: 1-12: ");
            int m=sc.nextInt();
            System.out.println("Enter the day of the month: 1-31: ");
            int q=sc.nextInt();

        Zellercongruence(q, m, year); //date (dd/mm/yyyy) 
        } 
}

Sample Output: