Question

Inheritance

Constructors

Accessibility

Accessibility Rules

private

        accessible within the same class.

unspecified (friendly) (default)

        additionally accessible to classes within the same package (folder).

protected

        additionally accessible to child classes.

public

        accessible to all classes.

Description

This assignment has two parts. Do the part I first and test it using the data in test run 1. Then do the second part and test it using data in test run 2 and test run 3. Submit the output from test run 1, 2, 3 and source code from both part I and II.

Part I.

Write a program that would determine the day number in a non-leap year. For example, in a non-leap year, the day number for Dec 31 is 365; for Jan 1 is 1, and for February 1 is 32. This program will ask the user to input day and month values. Then it will display the day number day number corresponding to the day and month values entered assuming a non-leap year. (See part II to this exercise below).

Optional:

Optionally provide the date validation code in the main method. The validation code will verify that the values entered by the user for the day and month are valid.

Implementation

For this exercise, create the following classes:

class Day

Create a public class Day that provides the following:

(This class keeps day and month value. It does not deal with a year value).

·       A private variable for holding day value.

·       A protected variable for holding month value.

·       A two-parameter public constructor to initialize day and month values

·       A public accessor methods getDay ( ) that returns day value.

·       A public accessor method getMonth ( ) that returns month value.

·       A public method findDayNum ( ) that calculates the day number corresponding to the day and the month values stored in the object. It calculates the day number assuming that it is a non-leap year.

class TestDay

Create a class TestDay containing the main ( ) method. In the main( ) method, do the following:

·       Prompt the user for entering day and month values.

·       Create an object of class Day and pass its constructor the day and month values entered by the user.

·       Call the method findDayNum( ) of Day object to obtain day number. (This does not take into account the leap year).

·       Display the original date and the day number for that date assuming that it is a non-leap year.

Testing:

Run the program use the following data:

Test Run 1:

Input:

Enter day

10

Enter month

3

Output:

Day Number for 3/10 is 69

PART II

Description

Enhance the above exercise so that it can determine the day number for both leap and non-leap years. This program will ask the user to enter the day, month, and year. Then it will display the day number corresponding to the date entered taking into account the leap year.

Implementation

Create the following two additional classes:

class LeapDay       

Create a LeapDay that extends the class Day created in part I and additionally provides the following:

·       A private variable year to hold the year value.

·       A public constructor with three parameters to initialize day, month and year values.

This constructor initializes the day and month values by calling the parent constructor.

·       A public accessor method getYear ( ) that returns the year value.

·       A public method findDayNum ( ) which over-rides the same method in the parent class and calculates the day number of the date stored in the object. It does the following:

1.     It accesses the day variable by calling the method getDay. Since day is defined private in the parent class, it cannot be accessed directly from the child class.

2.     It accesses the month variable directly. Since month is defined protected in the parent class, it can be accessed directly from the child class.

3.     It calls the parent method findDayNum and passes it day and month values from above. It receives the day number returned from the call calculated as if it is non-leap year.

4.     On return from the call to parent findDayNum above, it adds one to the day number received if it’s a leap year and the month is greater than 2

5.     It returns the day number to the caller of this method.

class TestLeapDay

Create a class TestLeapDay containing the main ( ) method. In the main( ) method, do the following:

·       Prompt the user to enter day, month and year values.

·       Create an object of class LeapDay and pass its constructor the day and month values entered by the user.

·       Call the method findDayNum( ) of LeapDay object to obtain the day number. (This method takes into account the leap year).

·       Display the original date and the day number for that date. For displaying the original date, call the object’s accessor methods.

Answer 1

please refer to below attached photos for clear understanding and implmentation of the program :

code :

import java.util.*;
import java.io.*;

class Day{
    private int day;
    protected int month;
    
    public Day(int day , int month){
        this.day = day;
        this.month = month;
    }
    
    public int getDay(){
        return day;
    }
    
    public int getMonth(){
        return month;
    }
    
    public int findDayNum(){
        int current_days = 0;
        for(int m=1;m<month;m++){
            if(m%2 == 0){
                if(m == 2){
                    current_days += 28;
                }
                else{
                    current_days += 30;
                }
            }
            else{
                current_days += 31;
            }
        }
        return current_days + day;
    }
}

class LeapDay extends Day{
    private int year;
    public LeapDay(int day , int month , int year){
        super(day , month);
        this.year = year;
    }
    
    public int getYear(){
        return year;
    }
    
    public int findDayNum(){
        int day_number = super.findDayNum();
        if((year % 4 == 0 || year % 400 == 0) && year % 100 != 0){
            if(month > 2){
                day_number += 1;
            }
        }
        return day_number;
    }
}

public class Main{
    public static void main(String[] args){
        Scanner in = new Scanner(System.in);
        System.out.print("Enter day : ");
        int d = in.nextInt();
        System.out.print("Enter month : ");
        int m = in.nextInt();
        Day day = new Day(d ,m);
        System.out.println("Day Number for "+day.getDay()+"/"+day.getMonth()+" is "+day.findDayNum());
        
        System.out.println("****************************");
        System.out.print("Enter day : ");
        int ld = in.nextInt();
        System.out.print("Enter month : ");
        int lm = in.nextInt();
        System.out.print("Enter year : ");
        int ly = in.nextInt();
        LeapDay lday = new LeapDay(ld ,lm, ly);
        System.out.println("Day Number for "+lday.getDay()+"/"+lday.getMonth()+" is "+lday.findDayNum());
        
    }
}