Author Archives: Mr. M

Account Abstract Class Assignment

This is the first part of a 2 part project.

Person Class

Constructor

public Person( String _name , int _age )

instance Variables

private String name
private int age

Methods

public String getName()
public int compareTo(Person other) { return this.age - other.age; }

Account – Abstract Super Class

Static Variable(s)

private static int nextAccountNum
private static int parentCompanyCode = 12810 ;

instance Variables

private int accountNumber// first account number should be 1
protected double balance
protected ArrayList<Person> owners

Constructor

public Account( double _balance, Person _owner) // add _owner to ArrayList owners

Methods

public static int getParentCode()
public int getAccountNumber()
public void deposit(double amount)
public double getCurrentBalance()
public abstract boolean withdraw(double amount)
public boolean equals(Account other) // are the unique account numbers equals ?
public String toString() Output should follow the conventions we have discussed. I will be testing for formatting like this :
public int comparesTo(Account other) { return this.accountNumber- other.accountNumber } (Note that this method has an ‘s‘ )
public void addOwner(Person p) //adds P to the ArrayList of owners
public ArrayList<Person> getOwners() // returns the ArrayList of owners
public Person remove( Person p) // this emulates the ArrayList’s remove() method (link) . Remember that that method removes the object and then returns the removed object. In this case, you should remove Person P from the ArrayList of owners

CheckingAccount extends Account
This class has to do certain things. You can decide the best way to do it. This class should have a way to
- attempt to withdraw money by writing a check. Every check should have a ‘check number’, which should be an integer. The lowest permissible value for a check number is 100 .
- public int writeCheck(double amount) // @ returns the check number of the written check
- public boolean cancelCheck(int checkNumber)
  - be able to cancel checks and keep track of the check numbers that have been cancelled
  - when a check is cancelled, the amount associated with that check is added back onto the balance.
  - return true if checkNumber is a valid check number; false otherwise.
One solution
- every time you write a check, you need a new check “#”
- writeCheck( double amount) - > tries to call this.withdraw(double amount) . You can then use ArrayLists to store check numbers, associated check amounts , things like that

SavingsAccount extends Account

instance variables

private double interestRate // //@ assumes that interest rate is not in decimal format i.e. 1.7 not .017

private ArrayList<Double> dailyBalances

static variables

public static final int MINIMUM_BALANCE=100; // this is the absolute minimum amount of money that must always be in the account

methods

public boolean withdraw(double amount) //@override the withdraw() method to ensure that currentBalance the never gets below MINIMUM_BALANCE

public void updateInterestRate(double newRate) //updates the interestRate

public void recordDailyBalance() // @ record current day’s balance by storing current balance in dailyBalances .

public ArrayList<Double> getDailyBalances() // @ return dailyBalances .

public double projectBalance(double timeInYears) // use the compound interest formula . Assume that the bank compounds the balance monthly. To learn more about how compound interest really works, click here .

You will need to convert interest rate from something like 1.7%, as an example , to 0.017

public void updateInterestPayment() // @ once a month update account based on average daily balances and interest rate.

*calculate the average monthly balance
* multiply balance by the interest rate (remember this must be converted to decimal)
* add that interest back onto the balance

public double getInterestRate()

public String toString() Output should follow the conventions we have discussed. I will be testing for formatting like this :

CertificateOfDeposit extends SavingsAccount

instance Variables

public static final double EARLY_WITHDRAW_PENALTY= 200 .

Methods

public boolean withdraw(double amount , boolean isEarly ) //@override the withdraw() and applies penalty to balance

Tester file :

import java.util.ArrayList;

public class Tester { 
    boolean verbose = false; //set to true for some expanded occasional error messages


    public Tester() {
        p2("Begin Testing");    
        p2("Version 4");    
        p2("set variable verbose to true if you want some occasional extra tips on errors");    
		p2("********************************************************************") ;
		p2("********************************************************************") ;
        doTest();
    }

    public void doTest(){

        int correct = 0;
        int wrong = 0;
        Person tyler = new Person("tyler", 18);
        Person joe = new Person("joe", 18);
        Person jim = new Person("jim", 17);

        if(tyler.compareTo(joe) == 0)
            correct++;
        else{
            p2("error @person, compareTo()");
            wrong++;
            }
        if(jim.compareTo(joe) == -1)
            correct++;
        else{
            p2("error @person, compareTo()");
            wrong++;
            }
        if(joe.compareTo(jim) == 1)
            correct++;
        else{
            p2("error @person, compareTo()");
            wrong++;
            }
        if( joe.getName().equals("joe"))
            correct++;
        else{
            p2("error @person, getName()");
            wrong++;

            }


        CertificateOfDeposit a = new CertificateOfDeposit(tyler, 120);
        double a_original_bal = a.getCurrentBalance();
        a.addOwner(joe);
        int a_num1 = a.getAccountNumber() ;    
		
		

        if (a_num1 != 1 ){
            wrong++    ;
            p2("First account 's id should be '1' ");
        }
        else 
            correct++;
    

        CertificateOfDeposit a2 = new CertificateOfDeposit(jim, 120);




    if(a2.getAccountNumber() <= a_num1){
            wrong++    ;
            p2("Unique account numbers not working correctly ");
        }
        else 
            correct++;


        if (a.getOwners().size() != 2)
            {
            p2("addOwner() not working ");
            wrong++    ;
            }
        else 
            correct++;

        a.remove(joe);
        if (a.getOwners().size() != 1)
        {
            wrong++ ;    
            p2("error , probably removeOwner() not working ");
        }
        else 
        {
            Person owner = a.getOwners().get(0);
            if(owner.getName().toLowerCase().equals("tyler"))    
                correct++;
            else
                {
                wrong++ ;    
                p2("error , probably removeOwner() not working ");
                }
        }


        if(Math.abs(a_original_bal - 120) > 0.000001)
		{
		p2 ("foo problem with setting  balance");
		wrong++;
		}
        else 
            correct++;


        
        a.deposit(25);
        if(Math.abs(a.getCurrentBalance() - 145) > 0.000001)
        {
            wrong++    ;
            p2("problem with setting  balance");
        }
        else 
            correct++;
        
        
        
        Person rob = new Person("rob", 18);
        CheckingAccount b = new CheckingAccount(rob, 200);
        b.deposit(500);
        b.withdraw(450);
        if( b.equals(a))
        {
        wrong++;    
            p2("Failed equals() test (Many things could cause this)");
        }
        else 
            correct++;

        if( a.equals(a) == false)
        {
        wrong++;    
            p2("Failed equals() test (Many things could cause this)");
        }
        else 
            correct++;


        double balanceNow = b.getCurrentBalance();
        int checkNum = b.writeCheck(4);
        // p2("checkNum : " + checkNum);
           if(checkNum >= 100) 
            correct++;
        else
        {
        wrong++;
        p2("error, Check Numbers cannot be lower than 100") ;
        }
       

        int check2Num = b.writeCheck(4);
        if(check2Num - checkNum == 1)
            correct++;
        else
        {
        wrong++;
        p2("error involving checknumbers. Should increment by 1") ;
        }

        if( balanceNow - b.getCurrentBalance() ==  8)
            correct++;
        else
            {
            wrong++;
            p2("Error involving writing checks and balance...could be various problems");
            if(verbose)
                p2("\t most likely your writeCheck() or withdraw() are the problem");
            }

        balanceNow = b.getCurrentBalance() ;
        int check3Num = b.writeCheck(242.1);

        if(check3Num - checkNum == 2)
            correct++;
        else
        {
        wrong++;
        p2("error involving checknumbers. Should increment by 1,even if the check bounces!") ;
        }

        if(balanceNow  == b.getCurrentBalance())
            correct++;
        else
        {
        wrong++;
        p2("Error involving bounced checks. You cannot withdrawal more than your current balance") ;
        p2("exiting testing program");
        return;
        }


        boolean badChkNum =  b.cancelCheck(50);
        if(badChkNum == false)
            correct++;    
        else
        {
        wrong++;
        p2("Error. cancelCheck on non existent check. Should return false, but didn't") ;
        p2("exiting testing program");
        return;
        }

        int check4Num = b.writeCheck(100);


        b.cancelCheck(check4Num);
        
        double balanceAferCancel = b.getCurrentBalance();
        if( balanceAferCancel == 242)
            correct++;
        else{
            wrong++;
            if(balanceAferCancel == 142)
                p2("cancelCheck() did not update balance. You still have deducted the amount for the check that is now cancelled");
            else
                p2("error , could be various things but most likely relateing to cancelCheck()/deposit()  ");
            }

        

        // if(balanceNow  == b.getCurrentBalance())
        //     correct++;
        // else
        // {
        // wrong++;
        // p2("Error involving bounced checks. You cannot withdrawal more than your current balance") ;
        // }


        Person roochi = new Person("roochi", 12);
        SavingsAccount c = new SavingsAccount(roochi, 110);
        boolean allGood = true;
        if(c.getCurrentBalance()== 110)
            correct++;
        else
        {
            allGood = false;
        wrong++;
        p2("error, could be constructor or getCurrentBalance()") ;

        }
        


        c.withdraw(5);
        if(c.getCurrentBalance()== 105)
            correct++;
        else
        {
            if(allGood )
                p2("error, probably withdraw()");
            else
                p2("error, could be constructor or getCurrentBalance() ") ;
        wrong++;
        }
        
        boolean isNull = false;
        try{
            
            c.addOwner(tyler);
        }
        catch( NullPointerException e){
        isNull = true;    
        
        }
    if(isNull)
        {
        p2("Looks like owners arraylist is null");
        p2("exiting program now, fix nullpointer first");
        wrong++;
        return;
        }
    else
        correct++;


//here 
// public String toString()





        Person james = new Person("Jim Adams II", 12);
        SavingsAccount jamesAcct  = new SavingsAccount(james , 666 );
        jamesAcct.addOwner(new Person("Jane Adams ", 34) );
        jamesAcct.addOwner(new Person("Jim Adams Sr", 35) );
        ArrayList<Person> owners = jamesAcct.getOwners();


        boolean anotherNull = false;
        try{
        jamesAcct.recordDailyBalance();
        }
        catch(NullPointerException e){
        anotherNull = true ;
        wrong++;
        }

    if(anotherNull)
        {
        wrong++;
        p2("NullPointer Exception Error, looks like you never initialized dailyBalances in SavingsAccount");
        p2("Exiting testing program");
        return;
        }
    else
        correct++;


    jamesAcct.updateInterestRate(3.3);

    if(jamesAcct.getInterestRate() == 3.3 )
        correct++;
    else{
        wrong++;
        p2("error, probably re: updateInterestRate()  or possibly getInterestRate()");
        }


    jamesAcct.recordDailyBalance();
    

    jamesAcct.deposit(22);
    jamesAcct.recordDailyBalance();
    jamesAcct.withdraw(100);
    jamesAcct.recordDailyBalance();
    jamesAcct.deposit(330);
    jamesAcct.recordDailyBalance();

     ArrayList<Double>  dailyBalances = jamesAcct.getDailyBalances(); 
    
    if(dailyBalances.get(0)== 666)
        correct++;
    else
        {
        wrong++;
        p2("error @ dailyBalances index 0");
        if(verbose)
            p2("\t\t 1st element of dailyBalances should be 666.00");
        
        p2("exiting testing program, fix daily balances first");
        return;
        }



    if(dailyBalances.get(1)== 666)
        correct++;
    else
        {
        wrong++;
        p2("error @ dailyBalances index 1");
        if(verbose)
            p2("\t\t 2nd element of dailyBalances should be 666.00");
        }
        
    if(dailyBalances.get(2)== 688)
        correct++;
    else
        {
        wrong++;
        p2("error @ dailyBalances index 2");
        if(verbose)
            p2("\t\t 3rd element of dailyBalances should be 666.00") ;
        }

    if(dailyBalances.get(3)== 588)
        correct++;
    else
        {
        wrong++;
        p2("error @ dailyBalances index 3");
        if(verbose)
            p2("\t\t 4th element of dailyBalances should be 588.00") ;
        }


    if(dailyBalances.get(4)== 918)
        correct++;
    else
        {
        wrong++;
        p2("error @ dailyBalances index 4");
        if(verbose)
            p2("\t\t 5th element of dailyBalances should be 918.00") ;
        }




    if( Account.getParentCode()== 12810)
        correct++;
    else{
        wrong++;
        p2("Account.getParentCode() wrong ");
        }

        //toString Tests
        String str = jamesAcct.toString();

    if(str.indexOf("SavingsAccount") == 0 )
        correct++;
    else{
        wrong++;
        p2("toString() should start w/classname. i.e. \"SavingsAccount\" ");
        }
    str = str.toLowerCase();

    if(str.contains("number") )
        correct++;
    else{
        wrong++;
        p2("toString() incorrectly formatted, Account number");
        }

    if(str.contains(jamesAcct.getAccountNumber() +"") )
        correct++;
    else{
        wrong++;
        p2("toString() incorrectly formatted, Account number");
        }

    if(str.contains("balance") )
        correct++;
    else{
        wrong++;
        p2("toString() incorrectly formatted, re: account balance");
        }

    if(str.contains(jamesAcct.getCurrentBalance() +"") )
        correct++;
    else{
        wrong++;
        p2("toString() incorrectly formatted, re: account balance");
        }

// ArrayList<Person> getOwners()    

    
    if(str.contains("owner") )
        correct++;
    else{
        wrong++;
        p2("toString() incorrectly formatted, re: Account Owners");
        }

    ArrayList<Person> jamesAcctOwners = jamesAcct.getOwners();
    for(Person p : jamesAcctOwners){
        String strName = p.getName().toLowerCase();
    if(str.contains(strName) )
        correct++;
    else{
        wrong++;
        p2("toString() incorrectly formatted, re: Account Owners");
        if(verbose)
                p2("\t\t " + str + "\n \t\t\t Missing " + strName);
        }
    }//end of for-each


    if(str.contains("interest rate") )
        correct++;
    else{
        wrong++;
        p2("toString() incorrectly formatted, re: interest rate ");
        }
    
    if(str.contains(jamesAcct.getInterestRate() + "") )
        correct++;
    else{
        wrong++;
        p2("toString() incorrectly formatted, re: interest rate ");
        }




    Person jorge = new Person("jorge", 17) ;
    CertificateOfDeposit cd_foo = new CertificateOfDeposit(jorge, 500);
    cd_foo.withdraw(100, true);
    double jorgesMoney = cd_foo.getCurrentBalance();
    if(jorgesMoney == 200 )
        correct++;
    else{
        wrong++;
        if( jorgesMoney == 400)
            p2("You did not apply the EARLY_WITHDRAW_PENALTY for a CD's early withdrawal");
        else
            p2("Certificate of Deposit has wrong balance after early withdrawal");

    }


Account sb = new SavingsAccount( jorge, 100 );
Account sb2 = new SavingsAccount( joe, 100);
if( sb2.comparesTo(sb) == 1)
	correct++ ;
else
	{
	wrong++;
	p2("Account's comparesTo not implemented correctly");
	}


SavingsAccount sb33 = new SavingsAccount( jorge, 100 );

sb33.updateInterestRate(3.3);
if( sb33.getInterestRate()== 3.3)
	correct++;
else
{
	wrong++;
	p2("Savings account error involving interestRate");
	p2("\t either getInterestRate() or , more likely, updateInterestRate() is wrong ");

}


double ball_yr1 = sb33.projectBalance(1);
if( Math.abs(ball_yr1 - 103.350372874721)< 0.000001)
	correct++ ;
else
	{
	wrong++;
	p2("SavingAccount's projectBalance() incorrect");
	}


	p2("********************************************************************") ;
	p2("********************************************************************") ;
	p2("                       SCORE  ") ;
	p2("********************************************************************") ;
	p2("********************************************************************") ;
	p2("********************************************************************") ;

    p2("-------------------------------");
    p2("Correct :  " + correct);    
    p2("Wrong   :  " + wrong);    
    
    }


void p2(String s){
    System.out.println(s);
}
void p2(int s){
    System.out.println(s);
}
void p2(boolean s){
    System.out.println(s);
}
    


}

Tester.java

When you are done, you can begin the Bank project .

The Case for Abstract Classes and Methods

Shape

download-bttn Shape Class

Constructor

public Shape( int _col)

instance Variables

protected int color

Accesor Methods

public abstract double getArea(); //returns the area of the triangle
public int getColor()
public void render() { System.out.println(“rendering shape” ) ; }

Now, let’s refactor our class relationships to represent our new Iheritance Tree

refactor all subclasses to reflect new class hierarchy
Update our new InteractiveMath class –InteractiveMath3

Circle Class

Create the following class

Circle

Circle
Constructor

public Circle( double _radius, int _col)

instance Variables

double radius
int color

Accesor Methods

public double getArea(); //returns the area of the triangle
public double getCircum() ;// returns the circumference

What should Circle Extend?

Answer!

Constructors And Inheritance

What relationships exist between super and sub classes?

How can we use superclasses to improve ourInteractiveMath2 code?
- To be implemented in computeNetArea() method
- How can an element in the Polygon2 ‘ list that is a RightTriangle2 call the getHypotenuse() method?
  - To be implemented in the new method void printDetails() which should , among other , things print the hypotenuse length for any RightTriangle2’s?
What is Inherited by subclasses?
- Constructors?
- instance variables
- static variables?

Next: What if we want to add a Circle Class

SuperClasses are Great II

How can we improve our current class structure? right_triangle_rectangle

We are going to create a second “Generation” of classes and will denote this change by appending a ‘2’ to the names of all classes in this “generation”

Class: Polygon2 (superclass of Triangle2, Rectangle2) Polygon2

Constructor

public Polygon2(int _col, double _width, double _height, int _sides)

instance Variables

private int color;
private int numSides
protected double width;
protected double height

Methods

public int getColor()
public double getWidth()
public double getHeight()

Class: Rectangle2 extends Polygon2 Rectangle2

instance Variables

None needed (see superclass)

Accesor Methods //override each of the superclass

public double getArea(); //returns the area of the triangle

Class: RightTriangle2 extends Polygon2 RightTriangle2

instance Variables

None needed (see superclass)

Accesor Methods //override each of the superclass

public double getArea(); //returns the area of the triangle
public double getHypotenuse()

InteractiveMath2 InteractiveMath2

Next: What is inherited?

Super Classes Are Great I

Question: What limitations seem to exist with our use of classes?

I. Implement all Methods of the Triangle and Rectangle methods below

Class: Rectangle Rectangle

Constructor

public Rectangle ( int _col, double _width, double _height)

instance Variables

private int color;
private double width;
private double height ;

Accessor Methods

public double getArea(); //returns the area of the rectangle
public int getColor()

Class: RightTriangle RightTriangle

Constructor

public RightTriangle( int _col, double _width, double _height)

instance Variables

private int color;
private double width;
private double height;

Accessor Methods

public double getArea(); //returns the area of the triangle
public int getColor()
public double getHypotenuse() ;

Class: InteractiveMath

download-bttn InteractiveMath-Arraylists (USE THIS ONE)

instance Variables

ArrayList<Rectangle> rectangles;
ArrayList<RightTriangle> triangles;

Accesor Methods

public double computeNetArea(){ //@ returns the area of the rectangles and triangles

Next : Super Classes are great 2

Then : constructors and inheritance.

after that : What is “Inherited” by Subclasses?

interactiveMath_arrays

isLeapYear assignment

Every year that is exactly divisible by four is a leap year, except for years that are exactly divisible by 100; the centurial years that are exactly divisible by 400 are still leap years. For example, the year 1900 was not a leap year; the year 2000 was a leap year

Call	return value
isLeapYear(100)	false
isLeapYear(4)	true
isLeapYear(104)	true
isLeapYear(400)	true
isLeapYear(800)	true
isLeapYear(5)	false
isLeapYear(803)	false

Seconds Since Birthdate

I . write bool isLeapYear( int year) : returns true or false depending on whether or not input is a leap year.

II. write a function called int secondsSince( int usersBYear, int usersBmonth, int usersBDay) .

This function should return the number of seconds since that bithdate (year, month, day)

III. In Main: use cout and cin to ask user for their bithdate and then display how many seconds since that person’s bithdate

IV. Determine how many seconds have occurred since 0/0/0 .

download-bttn Starting Code

PlayList Project [ArrayList]

A PlayList project will be based on 3 Classes

Artist
Song
PlayList

The Artist class will store core information about an artist.

The Song class will store basic information about a song.

The PlayList class will manage a list of artists and their ratings.

Tester files:

Artist and Song tester file SongArtistTester.v0 – run this after you have completed the Song and Artist classes and before PlayList. This way, you’ll know that you have correctly done the the foundation classes before moving onto PlayList
Some things about grading.
- do not use any external libraries aside from the ArrayList
- use proper naming conventions for instance variables, for methods and static methods
- make sure that you employ code re-use. (do not copy and paste code, but use methods that you have already written)

Artist

Constructor(s) :
- public Artist(String name)
Instance Variables
- private String artistName ;
- private ArrayList<Song> songs ; – an array storing the songs of this artist
Methods
- public void addSong(Song song) . Create a song object (see above) and add it to the arraylist. Here’s the first line.
- public String toString()
- public boolean equals(Artist other) //returns true if the names (only) are the same
- public ArrayList<Song> getSongs()
- public String getName()

Example of instantiating an Artist object and calling one of its methods:

Artist redHotChilliPeppers = new Artist("Red Hot Chili Peppers") ;
redHotChilliPeppers.addSong( new Song("Snow") );
ArrayList<Song> chiliSongs =redHotChilliPeppers.getSongs() ;

Artist redHotChilliPeppers = new Artist("Red Hot Chili Peppers") ;

redHotChilliPeppers.addSong( new Song("Snow") );

ArrayList<Song> chiliSongs =redHotChilliPeppers.getSongs() ;

Song

Constructor(s):
- public Song( Artist _artist, String _name)
Instance Variables
- private Artist artist
- private String name

Methods
- public String getName()
- public Artist getArtist()
- public boolean equals(Song other) //returns true if both the song objects have the same artist and name.
- public String toString()

Example of instantiating a Song object :

Artist redHotChilliPeppers = new Artist("Red Hot Chili Peppers") ;
Song underBridge = new Song (redHotChilliPeppers  , "Under the Bridge") ;

1 2	Artist redHotChilliPeppers = new Artist("Red Hot Chili Peppers") ; Song underBridge = new Song (redHotChilliPeppers , "Under the Bridge") ;

PlayList

Static Variable
- public static final int MAX_NUMBER_SONGS= 6 ;
Instance Variables
- private String listName ; This is the ‘name’ of your playList
- private ArrayList<Song> songs ;
- private ArrayList<Integer> stars ;//how many stars each song has
- Note: songs and stars are parallel ArrayLists
Constructor
- public PlayList(String name) : There should be only 1 constructor that takes a parameter representing the name of the playList
Accessor Methods
- public double averageRating() // returns the average star rating for the list
- public ArrayList<Song> getSongs() // returns the songs
- public double averageRating(Artist artist) // returns the mean star rating associated with artist
- public Song[] getSongs(Artist artist) // returns an array populated by the songs of parameter artist
- public ArrayList<Artist> getArtist(String songName) // returns an ArrayList of all Artists associated with the String songName (This could be multiple musicians. Cover songs etc..)
- private int indexOf(Song someSong) //
- public String toString() //returns an appropriate String representation of the PlayList . Here is an example of the toString() value for a PlayList I created.
- public String getName() // @returns the listName of the PlayList
- public ArrayList<Integer> getStars() //returns the stars ArrayList
Mutator Methods
- public void swap(Song song1 , Song song2, ) // switches positions of these two (maintain parallelism!)
- public boolean add(Song _song , int _stars)
  //adds data if number of song is less than MAX_NUMBER_SONGS
- public void removeSong(Song song) /removes all occurrences of song . There could be multiple instances of song. Maybe someone really likes a particular song and has it several times in one list. (Hint : Do not loop forwards)
- public void removeArtist(Artist artist ) //removes all elements associated with artist
- public void removeLowStars(int cutOff) //removes all elements associated with a star rating less than or equal to cutOff

The method’s below are extra credit. If you figure out how to do them, you must also meet with me after school about the methods. To receive the extra credit, be prepared for a mini-quiz on how they work. Be prepared for me to ask about your solution and how changing certain parts of your code would affect your solution. This meeting must happen on the Monday or Wednesday following the deadline.

** public PlayList sortByRating() //this returns a rearranged playlist so that the 5 starred elements are the first group in the list, 4 stars second …1 stars, last
- To do this , you should use a sorting algorithm. I suggest, Selection Sort (link). As this both intuitive and on the AP.
** public PlayList shuffle()/ /this returns a new PlayList in which all of the songs have been reordered randomly

When you’re done this, begin exploring different sorting algorithms with this online sorting detective :

https://labs.penjee.com/sort-detective/

Class Roster Java Assignment

Class Roster: This class will implement the functionality of all roster for school. It will , in essence, manage an ArrayList of Student objects.

Client file: tester file

Class or static variables
- Java
  
  public static final int MAX_NUM
  
  1
  
  public static final int MAX_NUM
  
  representing the maximum number of students allowed on the roster
Instance Variables
- Java
  
  ArrayList<Student> myStudents
  
  1
  
  ArrayList<Student> myStudents
  
  : an ArrayList storing Student Objects

int period

1	int period

//during which period of the day does this roster meet

Constructors

a default constructor should initialize the list to empty strings
single parameter constructor with the period as a parameter
Both constructors should initialize the instance variables

Methods

Accessors
- private int indexOf(Student st) //@returns index of Student St or -1
- public boolean contains(Student st) //@returns true if studentName is in roster
- public boolean contains(int ssnId) //@returns true if a student in the list has that SSN
- public int getPeriod() // returns period
- public Student retrieveBySSNId(int ssnId ) //@ returns Student associated with id. This should return null if the student does not exist.
- public boolean equals(ClassRoster other) //@ returns whether or not rosters are equal
- public ArrayList<Student> getStudents() //@returns the ArrayList of all students in the roster
- public String toString()

Mutators:

public boolean addStudent( Student st ) ;//if the size of the arraylist is less than MAX_NUM, add the student and return true; otherwise, return false and do not add student.
public boolean addStudent(String studentName, int age) ;//adds student name and age to end of roster
- Make sure that the total number of students does not exceed MAX_NUM.
public Student removeStudent(int ssnId ) // removes student from roster based on id.
public Student removeStudent(String name) //removes student based on name.
public Student removeStudent( Student st) //removes student st.

Mr. M online

Mr. M's Stuff

Author Archives: Mr. M

Account Abstract Class Assignment

Person Class

Account – Abstract Super Class

CertificateOfDeposit extends SavingsAccount

The Case for Abstract Classes and Methods

Shape

Circle Class

Circle

What should Circle Extend?

Constructors And Inheritance

What relationships exist between super and sub classes?

SuperClasses are Great II

Class: Polygon2 (superclass of Triangle2, Rectangle2) Polygon2

Class: Rectangle2 extends Polygon2 Rectangle2

Class: RightTriangle2 extends Polygon2 RightTriangle2

Super Classes Are Great I

Question: What limitations seem to exist with our use of classes?

Class: RightTriangle RightTriangle

Class: InteractiveMath

isLeapYear assignment

Seconds Since Birthdate

PlayList Project [ArrayList]

Artist

Song

PlayList

Class Roster Java Assignment