Question

Create a Java application named Problem14 using the two files Dr. Hanna provided to you—Date.java andProblem14.java—then change his code to add two non-trivial public, non-static methods to the Date class.

1. Increment a Date to the next day (for example, 1-31-2011 increments to 2-1-2011; 12-31-2010 increments to 1-1-2011).

2. Decrement a Date to the previous day (for example, 2-1-1953 decrements to 1-31-1953; 1-1-1954 decrements to 12-31-1953).

. Extra Credit (up to 5 points) Re-write the Date member functions Input() and Output() to usedialog boxes to accomplish input and output of Date objects.

//---------------------------------------------------------
// Date.java
//---------------------------------------------------------

package problem14;

import java.util.Scanner;

public class Date
{
private String name;
private int MM;
private int DD;
private int YYYY;
private char separator;

//----------------------------------------------------
public Date(String name,char separator)
//----------------------------------------------------
{
this.name = name;
MM = 12; DD = 1; this.YYYY = 1993;
this.separator = separator;
System.out.print("Date construction#1 of "); Output();
}

//----------------------------------------------------
public Date(String name,int MM,int DD,int YYYY,char separator)
//----------------------------------------------------
{
this.name = name;
this.MM = MM; this.DD = DD; this.YYYY = YYYY;
this.separator = separator;
System.out.print("Date construction#2 of "); Output();
}

//----------------------------------------------------
public void finalize()
//----------------------------------------------------
{
System.out.print("Date destruction of "); Output();
}

//-------------------------------------------------
public void Input()
//-------------------------------------------------
{
Scanner IN = new Scanner(System.in);

System.out.print(name + " MM? "); MM = IN.nextInt();
System.out.print(name + " DD? "); DD = IN.nextInt();
System.out.print(name + " YYYY? "); YYYY = IN.nextInt();
}

//----------------------------------------------------
public void Output()
//----------------------------------------------------
{
System.out.printf("%s = %2d%c%2d%c%4d\n",name,MM,separator,DD,separator,YYYY);
}

//-------------------------------------------------
public void SetMM(int MM)
//-------------------------------------------------
{
this.MM = MM;
}

//-------------------------------------------------
public void SetDD(int DD)
//-------------------------------------------------
{
this.DD = DD;
}

//-------------------------------------------------
public void SetYYYY(int YYYY)
//-------------------------------------------------
{
this.YYYY = YYYY;
}

//-------------------------------------------------
public String GetName()
//-------------------------------------------------
{
return( name );
}

//-------------------------------------------------
public int GetMM()
//-------------------------------------------------
{
return( MM );
}

//-------------------------------------------------
public int GetDD()
//-------------------------------------------------
{
return( DD );
}

//-------------------------------------------------
public int GetYYYY()
//-------------------------------------------------
{
return( YYYY );
}

//-------------------------------------------------
public int GetSeparator()
//-------------------------------------------------
{
return( separator );
}

//-------------------------------------------------
public void incrementDate()
//-------------------------------------------------
{
int[] daysInMonth = { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
// If leap year than Feb will contain 29 days
if (isLeapYear(this.YYYY))
{
daysInMonth[2] = 29;
}
/*
* increment days if no of days if more that the days of a month increment a
* month , if no of months ig greater that 12 then set it to 1 and increment a
* year
*/
this.DD++;
if (this.DD > daysInMonth[this.MM])
{
this.DD = 1;
this.MM++;
if (this.MM > 12)
{
this.MM = 1;
this.YYYY++;
}
}
}

//-------------------------------------------------
public void decrementDate()
//-------------------------------------------------
{
//missing code
}

public boolean isLeapYear(int year)
{
return ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0);
}

}

//---------------------------------------------------------
// Problem14.java
//---------------------------------------------------------

package problem14;

import javax.swing.JOptionPane;

public class Problem14
{
public static void main(String[] args)
{
Date date1 = new Date("date1",'-');
Date date2 = new Date("date2",1,5,1953,'.');

date1.SetMM(1);
date1.SetDD(30);
date1.SetYYYY(1979);
date1.Output(); System.out.println();

date2.Input();

// OMG! An example of an attempted violation of the principle of information hiding!!!
// System.out.printf("%s = %2d%c%2d%c%4d\n\n",date2.name,date2.MM,date2.separator,
// date2.DD,date2.separator,date2.YYYY);
// generates a syntax error that complains about name having private access in the class Date.

// This is the correct way to access private instance variables using accessor methods.
System.out.printf("%s = %2d%c%2d%c%4d\n\n",date2.GetName(),date2.GetMM(),date2.GetSeparator(),date2.GetDD(),date2.GetSeparator(),date2.GetYYYY());
  
date2.incrementDate();
System.out.println("Next Day is ");
date2.Output();
  
date1 = null;
date2 = null;

System.out.println("Just before System.gc() call...");
System.gc();

JOptionPane.showMessageDialog(null,"Pause execution...");

}
  
}

Answer 1

Answer: Suggest using simple java.util.lib

SimpleDateFormat Dateformat1= new SimpleDateFormat("dd-mm-yyyy");

Calender cal=Calender.getinstance();

//print the user input date

cal.set(31,Calender.JANUARY,2011);

System.out.println(Dateformat1.format(cal.getTime()));

//increment the date to next day and print the date

cal.add(Calender.DATE,1);

System.out.println(Dateformat1.format(cal.getTime()));

//Decrement the date by one day and print the date

cal.add(Calender.DATE,-1);

System.out.println(Dateformat1.format(cal.getTime()));