1992-2007 pearson education, inc. all rights reserved. 1 cs01 object-oriented programming: case...

1

1992-2007 Pearson Education, Inc. All rights reserved.

CS01

CS01Object-Oriented

Programming:Case Studies 01

2


Cases Studies

• A sales store

• Restaurant

• Registration System

• Course Scheduling System

• Reservation System

3


Other Cases

• ATM• Lone payment follow up

– A financial problem

• Simple edditor• Simple calculator• Simple games

– Tic-tac-too– Memory cards

• Agent-based simulation studies– e-auctions, service, production, markets

4


Relationship between Classes

• has a – composition

• E.g.:– A student has a(n)

• name, address, phone number

– A book has a• title, publisher,...• author or authors

– A bank has• accounts• customers

5


Relationship between Classes

• is a – inheritance

• E.g.:– A student is a person

• name, address, phone number

– A book is a document• author or authors, title, publisher,... From document

• Specific variables to books

– A dog is an animal• move – every animal moves

6


one to one Relationship

• A student has – one name,– one ID number

• A book has a• one title, one publisher,...

• A bank account• one code

• Imlementation:– instance variable – primitive or class– initialize with constructors– set methods for chaning– get methods for obtaining the values– Part of toString methods - String representation

7


one to many Relationship

• A store has many– products– employees– customers– branchs

• These are properties of each store object• 1 to many relationship

– one store has many customers, products.

• Implementation– instance variable – array of simple types or objcects– Constructor – initialise the array or get the array as a parameter

8



– Methods for– Adding new elemnents

• E.g.: adding new customers to a store• Adding new bank account to a bank• Adding new products

– Removing elements• Deleting customers• Closing accounts

– Searching elements• Find a particular customer, or account• How – search key

– index of the array – direct method (not practical)– Key – e.g.: customer ID, account ID.

9



– iterate over the elements• Searching,

• calculating totals

10


many to many Relationship

• student - course– each student can take many courses

– each course are taken by many students

• book - author– Each book may have many authors

– each authorr may wtite many books

• Emloyees – departments– each may work in more then one department

– each department has many employees

11


Composition and Inheritnece

• Person – Student: is a relation– Student is inherited from Person

• Person– attributes:

• name – String

• personID – String

– Constructors and methods• get, set methods

• toString method

12


Composition and Inheritnece

• Student– attributes:

• department – String

• schoolID – String

• others

– Constructors and methods• get, set methods

• toString method

– overrides toStirng of Person

• can reach: name, personID invoking get set methods of Person

13


Another design - Composition

• Student– attributes:

• person – Person– a person object is an instance variable– set name, personID on this object

• department – String• schoolID – String• others

– Constructors and methods• get, set methods• toString method

– overrides toStirng of Person• can reach: name, personID invoking get set methods over the person

instance variable in the studnet object

14


The ArrayList Class

• Array – store objects but – Once an Array is created its size is fixed

• Java ArrayList class to store unlimited number of objects

15


Some Methods of the ArrayList Class

• ArrayList()– Create an empty list

• void add(Object o)– Append a new element o at the end of the list

• void add(int index, Object o)– Add a new element o at the specifed index to the list

• void clear()– Removes all the elements from the list

• boolean contains(Object o)– Returns true if the lsit contains Object o

16


Some Methods of the ArrayList Class (cont.)

• Object get(int index)– Returns the element from the list at the specified index

• int indexOf(Object o)– Retuns the index of the first matching element in the list

• boolean isEmpty()– Returns true if the list is empty – contains no elements

• int lastIndexOf(Object o)– Returns the index of the last matching element

• boolean remove(Object o)– Removes the element from the list

17


Some Methods of the ArrayList Class (cont.)

• int size()– Returns the number of elements in the list

• boolean remove(int index)– Removes the element at the specifed index from the list

• Object set(int index, Object o)– Sets the element at the specified index

18


Comparing Array and ArrayList

• Creatng an Array/ArrayList– Object[] a = new Object[10];

– ArrayList list = new ArrayList();

• Accesing an element– a[index]

– list.get(index);

• Updating an element– a[index] = “London”;

– list.set(index,”London”);

19


Comparing Array and ArrayList (cont.)

• Returning size– a.length;

– list.size();

• Adding a new element– -

– list.add(“London”);

• Inserting a new element– -

– list. add(index,“London”);

20


Comparing Array and ArrayList (cont.)

• Removing an element– -

– list.remove(index);

– list.remove ( “London”);

• Removing all elements– -

– list.clear();

21


An Example Program

import java.util.ArrayList;public class ArrayListTest {

public static void main(String[] args) { ArrayList list = new ArrayList(); list.add("Ankara"); list.add("İstanbul"); list.add("İzmir"); System.out.println("size:"+list.size()); int i = list.indexOf("Ankara"); System.out.println("index of Ankara"+i); System.out.println("index of Ankara"+list.indexOf("kjk"));

22


An Example Program (cont.)

Integer j = new Integer(2); list.add(j); System.out.println("size:"+list.size());

int k = 2; list.add(k); System.out.println("size:"+list.size());

23



X x = new X(); list.add(x); System.out.println("index of x"+list.indexOf(x));

X y = (X)list.get(5);// downcasting is needed// returns Object- assigned to X-subclass System.out.println("value of y.a"+y.a); } // end main } // end ArrayListTst

24



class X {

public double a = 10;

}

25


AutoBoxing unboxing

• Boxing

• Integer a = Integer(2);

• a = 3; // possible a simple variable or constant is set as the value of a

• a.setValue(3);

• Unboxing

• int i;

• i = a; // unboxing the value eccapsuated in a is obtained and assigned to i

• i = a.getvalue();

26


Another Example – Simple Store

• A sale consits of products and how many are purchased from each

– Calculate total payment for a sale

• Classes:– Product

• attribute: price• methods: getPrice

– Sales• attributes: list of products - ArrayList• list of counts – ArrayList• methods: addProduct, cancleProduct,getTotal

27


Another Example – Simple Store

• Test Class: SaleTestAL

• create products: p1,p2,p3

• create sales: s

• add transactions to sale (products and their sold amounts)

• cancle transactions from sale (products and their sold amounts)

• list total payment of the sale

28


Sale class with ArrayList

class Sales{

private ArrayList productList = new ArrayList();private ArrayList count = new ArrayList();

public void addTransaction(Product p,int c){ productList.add(p); count.add(c);

} // end addTransaction

public void cancleTransaction(Product p){ int i = productList.indexOf(p); productList.remove(i); count.remove(i);

} // end cancleProduct

29


Sale class with ArrayList

public double getTotal(){

Product prd;int quant;double total=0.0;for(int i=0; i < productList.size();i++) {

prd = (Product)productList.get(i); quant = (Integer)count.get(i); total += prd.getPrice()*quant;

} // end for return total;

} // emd getTptal

} // end class Sales

30


Product class

class Product{private double price;

public Product(double p){ price = p;} // end constructor

public double getPrice(){ return price;} // end get price

} // end class Product

31


StoreTestAL class

import java.util.*;

public class StoreTestAL { public static void main(String[] agrs) { Sales s = new Sales(); Product p1 = new Product(5); Product p2 = new Product(10); Product p3 = new Product(20);

32


s.addTramsaction(p1,1);



s.cancleTramsaction(p3);

System.out.println("total:"+s.getTotal());

}// end main

} // end StoreTestAL

33


Sale class with Collection version

class Sales{ private ArrayList<Product> productList = new ArrayList<Product>(); private ArrayList <Integer>count = new ArrayList<Integer>();

public void addTransaction(Product p,int c){ productList.add(p); count.add(c);

} // end addProduct

public void cancleTransaction(Product p){ int i = productList.indexOf(p); productList.remove(i); count.remove(i);

} // end cancleProduct

34


Sale class with Collection version

public double getTotal(){

double total=0.0;for(int i=0; i < productList.size();i++) {

total += productList.get(i).getPrice()

*count.get(i);} // end for return total;

}

} // end class Sales

35


ArrayList Collections

ArrayList<T> name = new ArrayList<T >();

T ploaceholder for a nonprimitive type

ArrayList<String> name = new ArrayList<String>();

ArrayList<Integer> name = new ArrayList<Integer>();

ArrayList<Product> name = new ArrayList<Product>();

36


Store Problem extended

• Extension of the simple store• Sell products to customers with different promotion types

by sale persons with different premiums from these sales• What are classes

– Product– Person– Employee– Customer– Promotion

• These are nouns in the requirement statement so definetly classes. Others?

– What about sales?

37


Product Class

• products– product hierarchy

– abstract product class• instance variables - name,code,price

• - stock

• methods – increase or decrease stock

– subclasses• food, cleaning, electironic, textile

• Food:

– Bevarages, meat..

38


Product Class

• products

• here for simplisity no hierarchy

• products are defined in Store class

• What about promotion?– When sold apply a prootion

39


Product class – instance variables

class Product {

private String name ;

private int stock;

private double price;

private Promotion prm;

;

40


Product class - constructors

public Product(String productName,int productStock, double price,Promotion promotion) { this(productName,productStoc, price); this.prm = promotion; } // end of constructor

public Product(String productName,int productStock, double price) { name = productName; stock = productStock;//can be set with verification by set methods

this.price = price; } // end of constructor

41


Product cass - methods

public int dropStock(int amount) { if(amount <= stock) { stock -= amount; return amount; } return 0; } // end dropStock public int getstock() { return stock;} // end getStock

42


Product get methods

public Promotion getPromotion () { return prm;} public double getPrice() { return price;}

43


Product set methods

public void setPromotion (Promotion p) { prm = p;} public double setPrice(double p) { price = p;} }// end class Product

44


Person Class

• Personal characteristics

• Super class of customers and employees

45


Person Classes Code

class Person { protected String name;

// may have other attributes

public Person(String name) {

this.name = name;

} // end of constructor

// may have other methods

} // end class Person

46


Cusomer

• Customer– general customer – abstract class– loyal – non loyal customers– loyal: having a kind of purchaseing card– loyal customers has subclasses as well

• gıolden , silver, ...card customers

– different point accumulation methods– Sale promotions may apply differently

• rules of organization

– may extend from a person class• inharits name address, birthDate ... from a Person class

47


Customer Classes

abstract class Customer extends Person { protected double point; public Customer(String name) { super(name); } public double getpoint() { return point; } abstract protected double payment(double x); } // end Customer class

48


Customer Classes

class Gold extends Customer {

private static double goldPointRate = 0.1; public Gold(String name) {

super(name); }

public double payment(double amount) { point += amount*goldPointRate;

double pointsUsed =Sales.askPoints(point); point -= pointsUsed;

return amount - pointsUsed;

} // end payment} // end class Gold

49


Customer Classes

abstract Silver extends Customer{

private static double silverPointRate = 0.05; private static double limit = 20;

public Silver(String name) {

super(name); }

public double payment(double amount) {

if (amount > limit)point += (amount-limit)*silverPointRate;

double pointsUsed =Sales.askPoints(point);

point -= pointsUsed;return amount - pointsUsed;

} // end payment } // end class Silver

50


Employee

• Employee – employee class – abstract class

– employees get preimium from the sales they made

– premium depends on the amount of sales and type of employee along the hierarchy

– Gets the amount of sales as parameters, calculates the premium depending on the type of employee and returns the premium

• As both customers and employees are persons they may extend from a Person class

51


Employee

• Emloyee

• three types of employees– type1: commission is proportional to the sales they made

(similar to the commissionEmployee class we covered in Chapter 9-10)

– type2: get premium if the amount of sales exceeds a lower limit• make the limit 0 then convert to type1

– type3: get premium if total sales they made in a say month exceeds a prespecifed limit• hold total sales they made not from a single transaction

52


Employee classes

abstract class Employee extends Person {

public Employee (String eName) { super (eName); }

public abstract double premium(double amount);

} // end class Employee

53


Employee classes

class Salaried extends Employee { private static double commissionRateSalaried = 0.05; private static double limitSalaried = 100.00; private double totalSales;

public Salaried (String eName) { super (eName); } // end constructor public double premium(double amount) { totalSales += amount; if(totalSales < limitSalaried)

return 0.0; else return amount*commissionRateSalaried;

} // end premium} // end class Salaried

54


Employee classes

class Commissioned extends Employee { private static double commissionRate = 0.10;

public Commissioned (String eName) { super (eName); } // end constructor public double premium(double amount) { return amount*commissionRate; }} // end class Salaried

55


Promotion

• promotion– different promotion types defined

• How to define promotion – a product has a promotion

• instance variable of product• default value may be no promotion – most products• may change over time – assign different promotions to a

product by the setPromotion method• promotion may interract with customer type

– certain promotions may be applied to different customers

• depends on how much purhased as well

56


Promotion class

• abstract class

• Each broad category of prootion is a subclass of the abstradt promotion

• Are associated with products

57


Promotion class

public abstract class Promotion {

protected String proName;

public Promotion(String n){

proName = n;

}

public abstract double payAfterProm(int q, Product p);

} // end of class Promotion

58


Promotion class

public class Discount extends Promotion { private double discountRate; public Discount(String n,double dr){ super(n); setDiscountRate(dr); } public double payAfterProm(int q, Product p) {

double gross = q*p.getPrice(); return gross*(1-discountRate); }} // end of class Discount

59


Promotion class

public class GetMore extends Promotion { public Discount(String n){ super(n); } public double payAfterProm (int q, Product p) {

p.setStocks(q+q/2); double gross = q*p.getPrice(); return gross; }} // end of class GetMore

60


Sales

• In general Sales – transaction• involves

– a customer (null or a customer type for layal customers)– a sales person who made the sale (obtional)– list of products each optionally are sold with a different

promotion type

– other variables • a branch of a store (optional)• time of sales for return or service information or other bookkeeping

activities such as accounting• how the payment is made – in cash or credit card..• variables related to security

61


Sales

• A concept like sales• seems to be an action but involves many objects

(single – customer or list - products)• Examine the sentences:

– customer makes a purchase buying• bread, apple....• on 04.07.2009:17:25

– shoud it be a method of customer – a behavior of customer– or products are sold

• apple is purchased by customer X on a day

– should it be a method of product

62


Sales

• Define it as a new class although is is an action or behavior of customers or products

• As a sales action involves many objects

• Treat as a moun rather than worb selling

63


Sales class – variables

Customer customer; // a Customer object

Emloyee emp;

List of products purchased and their quantities are hold in arrays or ArrayLists

Other variables holding total revenue, total premium paid to employees

These variables should be static

They are classwide , not specific to a single sale

64


Sales class - constructors

Constructors can be overloaded

Chain of constructor calls with this

İf a loyal customer exists or the empleyee responsible from the sale is known they are recorded

Products and quantites are initilized

65


Sales class – adding or canceling products

• add

• Adds products and their amounts to the basket– Add products and quantities to relevant ArrayLists or arrays

• Cancel

• Takes a product reference removes it from the basket of products

66


Sales – calculating invoice

• As the last operation

• calcuate the payment of the customer– how much to pay considering

• promotion of indivdual products

• promotions specific to customer types

• decrease stock of products

• accumulate points or customers may use some points

– calculate premium for the employee

• Update total premium, total payment

67


Sales class –variables

class Sales {

private Customer customer;

private Employee saleEmployee;

private ArrayList<Integer> quantities;

private ArrayList<Product> basket;

private static double totalnetRevenue = 0.00;

private static double totalPremium = 0.00;

68



public Sales(Customer customer,Employee saleEmployee)

{

this(saleEmployee);

this.customer = customer;

}

public Sales(Employee saleEmployee)

{

this();

this.saleEmployee = saleEmployee;

}

69



public Sales(Customer customer) {

this();

this.customer = customer;

}

public Sales() {

quantities = new ArrayList<Integer>();

basket = new ArrayList< Product >();

}

70


Sales class - methods

public void add(Product product,int howMany) {

basket.add(product); quantities.add(howMany);}

public void cancel(Product p) { int i basket.indexOf(p);

basket.remove(p); if (i >=0) quantities.remove(i);}

71



public void invoice() { double premium = 0.0; double netRevenue = 0.0; double revenue = payment();

if(saleEmployee != null) { premium = saleEmployee.premium(revenue); totalPremium += premium; }

if(customer != null) netRevenue = customer.payment(revenue); else netRevenue = revenue; totalNetRevenue += netRevenue; System.out.println("Revenue: "+revenue); System.out.println(“net Revenue: "+netRevenue); System.out.println("Premium: "+premium);}

72



private double payment() { double total = 0.0; for(int i=0; i<basket.size(); i++) {

Product pr = basket.get(i); int q = quantities.get(i); Promotion p = pr.getPromotion(); total += p. payAfterProm(q,pr);

} return total;} // end method payment

73



public static double askPoints(double point)

{

Scanner input = new Scanner(System.in);

System.out.println("Your points:"+point);

System.out.print("How many points to use:");

return input.nextDouble();

}

} // end class Transaction

74


TestStrore class

import java.util.Scanner;public class TestStore { public static void main(String[] args) { Store myStore = new Store(); myStore.operate();

} // end of main} // end of TestStore

can be done even without creating a Store reference like that public static void main(String[] args) { new Store().operate();

// a Store object is created and its operate() method is invoked } // end of main } // end of TestStor

75


Store class code

class Store { private Product[] products; private Customer[] customers; private Employee[] employees; private Promotion[] promotions;

public Store() { products = new Product[10]; customers = new Customer[10]; employees = new Employee[10]; promotions = new Promotion[10]; }

76


Store class

public void operate() {

// create customers

customers[0] = new Gold("ali");

customers[1] = new Silver("ahmet");

// create promotions

promotions[0] = new Discount(“todaysdis",0.10);

promotions[1] = new Discount(“weeklydis",0.05);

promotions[2] = new GetMore(“one more for two");

77


Store class

// create products

products[0] = new Product("apple",30,6.0,promotions[0]);

products[1] = new Product("chocklate",40,5.0);

products[2] = new Product("milk",40,2.5,promotions[2]);

products[3] = new Product("ball",20,2.0);

78


Store class

// create employees employees[0] = new Salaried("hasan");

employees[1] = new Commissioned("ayşe");

Sales s1 = new Sales(customers[0]);s1.add(products[1], 2);s1.add(products[2], 3);s1.invoice();

Sales s2 = new Sales(customers[0],employees[1]);s2.add(products[1], 2);s2.add(products[2], 3);

s2.cancel(1);s2.invoice();

} // end of opertate method } // endof Store class

79


Restaurant

• meals – products– each meal has ingredients

• array of items – defined in the products

– all of its ingredients’ stoks dimenishes

– weiters should be promoted for the table they serve

– orders are made tablewise• customers are tables

• The restorant has many tables

– other ordering types – home services

80


Restaurant

• Similar to strore sales in many asects but has some differences

– Produces meals from raw materials– Do not consider kitchen scheduling or supply chain yet

• When a meal is ordered– its ingredients stoks dimenishes

• Ready products – Bevarages– Not have ingredients

• A product hierarchy. – Products:

• Meals – produced in the restoran• Others – purchased

81


Restaurant

– Premium policy

– Weiters get premium from the orders

– Head weiters get some small commissins as well

– There are couple of cooks – for each type of meal they are also paid a commission

• Emloyee hierarchy– Employee – abstract

• Cooks - concrete

• Weither - abstract

– Ordinary weiter - concrete

– Weither - concrete

82


Restaurant - Products

• Meal extends from product• Bevarages extends from product• Product class – abstract class

– instance variables• name – String• price – double

– Constructors• Set neme and price when creating a product

– Methods:• Order a product by customer - abstract• toString

83


Restorant - Products- Meals

• Each meal has – ingredient list

– Customer may customize some of them • How to imlement such a customization in java

– Has a cook to produce

– Type information – discrete broad categories

• inherits from products

• implements the order method– Decrease stocks of the desired ingredients

• toString method – overrides the toString in Product

84


Restaurant - Products- Bevarages

• Each bevarages has – A type information

• Constructor

• Order mehtod – implemnt the abstact method

• toString method– Override the Products

85


Restorant - Tables

• The restaurant has many tables– List of array– Each table is assigned a weiter – Either:

• Each table has a head weither• Or each weiter has a head weiter

• Methods– addOrder

• Add a product (meal or bevarages) and haw many are ordered• When spefifying a meal a customer may exclude some of its ingredients

– Cancel a product – Total payment

• Premium weiters and cooks– ClearTable

• After payments ready for new customers

86


Restorant - Emloyee

• Variables– Name, ssn,

• Constructors

• Methods– get, set methods

– premium – abstract

– toString

87


Restorant - Cook

• Variables– Type of meals

– Commission rate – static double

• Constructors

• Methods– get, set methods

– premium – amount*commissionRate

– toString

88


Restorant - weiter

• Variables• Constructors• Methods

– get, set methods– premium – abstract– toString

• ordinaryWeiter and headWeiter classes– Extends from weiter– Static commissionRate different– Premium method – amount*commissionRate

89


Restorant - Test class

• creates – list of tables

• order of meals or bevargages

• bill for payng the bill

– list of meals• ingredients

– list of cooks• assing to meals

– list of weithers• assing to tables

90


University Registration System

• students take courses– can or can not taken some courses

• prerequisites

• cotas

• other restrictions

• students – takes courses, withdraw a course

– general or semester point averages

• instructors– give courses, give grades to students

91


Requirements

• Students should take, drop courses

• Can display their transcripts

• Instructors can give grades see lsit of students

• Registration

92


Two design alternatives

• Taking a course, droping a course, displaying transcripts are actions of students so they are methods of the student class

• Giving grades displaying course lists are actions of instructors so should be methods of instructors

93


classes

• person class – abstract

• Concrete subclasses – Student

– instructor

94


class Student

• Student class extends from Person• ınstance variables

– name – String from Person– birthDate - Date: object from Person– advisor - Instructor: object – transcript – list of courses– program – list of courses

• Constructor(s)• Methods

– add a course– drop a course– display personal information– display transcript– other get and set methods

95


class Instructor

• Instructor extends from Person

• Instance variables– name from Person

– Title

– department

• Constructor(s)

• Methods– Give grades

– See student list in a course

96


class Course

• Course class• Instance variables

– code - String– name of the course – String– credit – integer– description – String– prerequisites – list of courses

• array or arraylist of courses– Cotas – for the time being cota is a variable of course

• İn an extended version cota is a varble of a sctionTerm • MIS 233.01 in FAll 2009 is different frım• MIS 233.01 in Spring 2008 is different frım or• MIS 234.01 in Spring 2009 is different frım • MIS 234.02 in Spring 2009 is different frım

97


class Course

• Course class

• Instance variables– code - String

– name of the course – String

– credit – integer

– description – String

– prerequisites – list of courses

98


classes

• list of students

• list of courses

• many to many relationship

99


Class TestClass

• Test class• Registration : objects represents terms

– Open method for carrying opperations

• Person– instance variables

• Name

• Instructor– instance variables

• coursesGiven: array of Courses given by this instructo

– Actions by methods• Give a course• Give grades in a term for a particular student in a particular course

100


Classes

• Course– Variables

• courseName• Credit

– Methods• get and set methods and toString

• Student– instance variables

• inherits name from Person• Courses taken grades if given

– Behavior by methods• Add a course• Set grade• Calculate gpa• Display transcript

101


Class - RegistrationTest

• public class RegistrationTest {

• public static void main(String[] args) {•

• Registration registration = new Registration();• registration.open();•

• } // end method main• } // end

102


Class - Registration

class Registration {

public Registration() {

} // end constructor

// starts registration opperationspublic void open() {

// create studentsStudent s1 = new Student("ali");Student s2 = new Student("ayse");

// create coursesCourse c1 = new Course("MIS 236",4);Course c2 = new Course("MIS 224",3);

// add courses to studentss1.addCourse(c1);s1.addCourse(c2);s2.addCourse(c1);s2.addCourse(c2);

103


Class – Registration (cont.)

// print transcripts of studentss1.transcript();s2.transcript();// greate instructorsInstructor i1 = new Instructor("bertan");Instructor i2 = new Instructor("hande");

i1.giveCourse(c1);i2.giveCourse(c2);

i1.giveGrade(c1, s1,2.0);i2.giveGrade(c2, s2,4.0);

// reprint transcripts of studentss1.transcript();s2.transcript();

} // end method open} // end class Registration

104


Class - Person

class Person {

private String name;

public Person(String name) {this.name = name;


// display personpublic String toString() {

return String.format("name: \t%s",name);}


105


Class - Student

class Student extends Person {

private Course[] courses; // course arrayprivate double[] grades; // array of gradesprivate boolean[] gradeEntered; // true if grades are enterredprivate int count; // number of courses taken

public Student(String name) {super(name);courses = new Course[10];grades = new double[10];gradeEntered = new boolean[10];


106


Class – Student (cont.)

// add a coursepublic void addCourse(Course c) {

count++;courses[count] = c;

}

// get index of courseprivate int getIndex(Course c) {

for(int i = 1; i <= count; i++) if(courses[i].equals(c)) return i; return -1;

}

107



// compute gpa of studentpublic double gpa() {

int points = 0;double total = 0.0;

for(int i = 1; i <= count ; i++)if (gradeEntered[i]) {

total += courses[i].getCredit()*grades[i];points += courses[i].getCredit();

} // end ifreturn total / points;

} // end method gpa

108



// seting grade of a coursepublic boolean setGrade(Course c,double grade) {

int i = getIndex(c); if(i>0) { grades[i] = grade; gradeEntered[i] = true; return true; } return false;

}

109



public void transcript() {System.out.printf("%s \n %s \n",

"Trascript of ", super.toString());

for(int i = 1; i <= count; i++) System.out.printf("%s\t%s\n",courses[i],

(gradeEntered[i]) ? String.format("%3.1f",grades[i]):"");

} // end method transcript

} // end class Student

110


Class – Student (with ArrayList)


private ArrayList<Course> courses; // ArrayList of Course

private ArrayList<Double> grades; // arrayList of Double

public Student(String name) {

super(name);

courses = new ArrayList<Course>();

grades = new ArrayList<double>();


111


Class – Student (with ArrayList)(cont.)

// add a coursepublic void addCourse(Course c) {

courses.add©; grades.add(null);

}

// seting grade of a coursepublic boolean setGrade(Course c,double grade) {

int i = courses.indexOf(c); if(i >=0) { grades.set(i,grade); return true;

} else return false;

}

112



// compute gpa of studentpublic double gpa() {

int points = 0;double total = 0.0;for(int i = 0; i < courses.size() ; i++)

if (grades.get(i)!=null) { total +=

courses.get(i).getCredit()*grades.get(i);points += courses.get(i).getCredit();


} // end method gpa

113



public void transcript() { System.out.printf("%s \n %s \n",

"Trascript of ", super.toString());

for(int i = 0; i <courses.size(); i++) System.out.printf("%s\t%s\n",courses.get(i),

(grades.get(i) != null) ?

String.format("%3.1f",grades.get(i)):"");} // end method transcript


114


Class –Instructor

class Instructor extends Person {

private Course[] givenCourses;private int count;

public Instructor(String name) {

super(name); givenCourses = new Course[3]; } // end constructor

115


Class –Instructor (cont.)

public void giveCourse(Course c) {

count++;

givenCourses[count] = c;

}

public void giveGrade(Course c, Student s, double g) {

s.setGrade(c,g);

}

} // end class Instructor

116


Class –Instructor (with ArrayList)


private ArrayList<Course> givenCourses;

public Instructor(String name) { super(name);

givenCourses = new ArrayList<Course>(); } // end constructor

117


Class –Instructor (with ArrayList) (cont.)


givenCourses.add(c);

}

public void giveGrade(Course c, Student s, double g) {

s.setGrade(c,g);

}


118


Class - Course

class Course {

private String courseName;private int credit;

public Course(String cName, int cCredit) {courseName = cName;credit = cCredit;


public int getCredit() {return credit;

}

// display coursepublic String toString() {

return String.format("name: \t%s\t%2d",courseName,credit);}

} // end class Course

119


Second Design Option

• Course – student – Many to many relation

• Relational approach• Create two arrays representing a table• One holding students the other courses• i th index of the arrays hold

– Students[i] = s1;– Courses[i] = c1;– Student s1 takes course c1 – Hold in index i

120


Second Design Option

• Greate two more arrays for holding grades information

– grades[i] = 4.0– At i th index for student s1, course c1 grade is 4.0

• When a student takes a course– A new element is added to the arrays– Just like adding another rew to a table in a relational

database

• Then, list courses , transcript, gpa – like methods opertate over the class containing the arrays

121


Class – Registration2Test

public class Registration2Test {

public static void main(String[] args) {

Registration2 registration = new Registration2();registration.open();

} // end method main} // end

122


Class – Registration2

class Registration2 {

// starts registration opperationspublic void open() {

// create studentsStudent s1 = new Student("ali");Student s2 = new Student("ayse");

// create coursesCourse c1 = new Course("MIS 236",4);Course c2 = new Course("MIS 224",3);

// create a termCourseTaken term = new CourseTaken();

123


Class – Registration2 (cont.)

// students take courses in that termterm.takeCourse(c1,s1);term.takeCourse(c2,s1);term.takeCourse(c1,s2);term.takeCourse(c2,s2);

// student list of coursesterm.courseList(c1);term.courseList(c2);

// print transcripts of studentsterm.transcript(s1);term.transcript(s2);

// greate instructorsInstructor i1 = new Instructor("bertan");Instructor i2 = new Instructor("hande");

124


Class – Registration2 (cont.)

i1.giveCourse(c1);

i2. giveCourse(c2);

i1.giveGrade(term,c1,s1,2.0);

i2.giveGrade(term,c2,s2,4.0);

// reprint transcripts of students

term.transcript(s1);

term.transcript(s2);

} // end method open

} // end class Registration

125


Class - Person

class Person {

private String name;

public Person(String name) {

this.name = name;


// display personpublic String toString() {

return String.format("name: \t%s",name);}


126


Class - Student


public Student(String name) {

super(name);



127


Class – Instructor (cont.)


private Course[] givenCourses;private int count;

public Instructor(String name) {

super(name); givenCourses = new Course[3]; } // end constructor

128


Class – Instructor (cont.)


count++;

givenCourses[count] = c;

c.setInstructor(this);

}

public void giveGrade(CourseTaken t, Course c, Student s, double g) {

t.setGrade(s,c,g);

}


129


Class – Instructor (with ArrayList)

class Instructor extends Person {private ArrayList<Course> givenCourses;public Instructor(String name) { super(name); givenCourses = new ArrayList<Course>(); } // end constructor

public void giveCourse(Course c) { givenCourses.add(c); c.setInstructor(this);}public void giveGrade(CourseTaken t, Course c, Student s, double g) { t.setGrade(s,c,g);}


130


Class –Course

class Course {

private String courseName;private int credit;private Instructor courseInst;

public Course(String cName, int cCredit) {

courseName = cName;credit = cCredit;


public int getCredit() {

return credit;}

131


Class – Course (cont.)

public void setInstructor(Instructor inst) {

courseInst = inst;

} // end method setInstructor

// return instructor of the coursepublic Instructor getInstructor() {

return courseInst;

} // end method getInstructor

// display coursepublic String toString() {

return String.format("name: \t%s\t%2d",courseName,credit);}

} // end class Course

132


Class –CourseTaken

class CourseTaken {

private Course[] courses;private Student[] students;private double[] grades;private boolean[] gradeEntered;private int count;

public CourseTaken() {

courses = new Course[20];students = new Student[20];grades = new double[20];gradeEntered = new boolean[20];

} // end contructor

133


Class –CourseTaken (cont.)

public void takeCourse(Course c,Student s) {

count++;courses[count] = c;students[count] = s;

} // end courseTaken method

// course listspublic void courseList(Course c) {

System.out.println("Course List");System.out.printf("%s\n",c.toString());for(int i = 1 ; i <= count ; i++ )

if(courses[i].equals(c))System.out.printf("%s\n",students[i].toString());

} // end method courseList

134



// transcript of studentspublic void transcript(Student s) {

System.out.println("Transcript");System.out.printf("%s\n",s.toString());for(int i = 1 ; i <= count ; i++ )

if(students[i].equals(s))System.out.printf("%s\t%s\n",courses[i],

(gradeEntered[i]) ? String.format("%3.1f",grades[i]):"");


135



// get index of course by student

private int getIndex(Course c, Student s) {

for(int i = 1; i <= count; i++)

if(courses[i].equals(c) && students[i].equals(s) )

return i;

return -1;

} // end method getIndex

136



// compute gpa of studentpublic double gpa(Student s) {


for(int i = 1; i <= count ; i++)if (gradeEntered[i] && students[i].equals(s)) {

total += courses[i].getCredit()*grades[i];points += courses[i].getCredit();


} // end method gpa

137



// seting grade of of a student at index ipublic boolean setGrade(Student s, Course c,double grade) {

int i = getIndex(c,s); if(i >=1) { grades[i] = grade;

gradeEntered[i] = true; return true; }

else return false;

} // end method setGrade

} // end class CourseTaken

138


Class –CourseTaken(with ArrayList)

class CourseTaken {

private ArrayList<Course> courses = new ArrayList<Course>();

private ArrayList<Student> students = new ArrayList<Student>();

private ArrayList<Double> grades = new ArrayList<Double>();

// default constructor

public void takeCourse(Course c,Student s) {

courses.add(c);

students.add(s);

grades.add(-1.0);

} // end courseTaken method

139


Class –CourseTaken(with ArrayList) (cont.)

// course lists

public void courseList(Course c) {

System.out.println("Course List");

System.out.printf("%s\n",c.toString());

for(int i = 0 ; i < courses.size() ; i++ )

if(courses.get(i).equals(c))

System.out.printf("%s\n",students.get(i).toString();

} // end method courseList

140



// transcript of students

public void transcript(Student s) {

System.out.println("Transcript");

System.out.printf("%s\n",s.toString());

for(int i = 0 ; i < students.size() ; i++ )

if(students.get(i).equals(s))

System.out.printf("%s\t%s\n",courses.get(i),

(grades.get(i) > -0.5) ?

String.format("%3.1f",grades.get(i)):"");


141



// get index of course by student

private int getIndex(Course c, Student s) {

for(int i = 0; i < students.size(); i++)

if(courses.get(i).equals(c) && students.get(i).equals(s) )

return i;

return -1;

} // end method getIndex

142



// compute gpa of studentpublic double gpa(Student s) {


for(int i = 0; i < students.size() ; i++)if (grades.get(i) > -0.5 && students.get(i).equals(s)) {

total += courses.get(i).getCredit()*grades.get(i);points += courses.get(i).getCredit();


} // end method gpa

143



// seting grade of of a student at index ipublic boolean setGrade(Student s, Course c,double grade) {

int i = getIndex(c,s);if(i>=0) { grades.set(i,grade); return true;} else return false;

} // end method setGrade

} // end class CourseTaken

144


Course Scheduling Problem

• for a given semester prepare a timetable for the courese offered in that term:in what room, when, considering also other constraints such as

– at a given time no two course can be scheduled in one room

– any instructor can not give two course at the same tim

– two courses of the same program year can not be at the same time• Teo frashmen courses, senior courses can not be confilicted

• Externsions– Capacity of rooms and number of students in each course

– Requirements of instructors – data show availiability in rooms

145


Reservation Problem

146


Quiz 3 Solution

public interface Asset { double taxPayment();}public abstract class Vehical implements Asset {}public class Building implements Asset { private double area; public Building(double a) { area = a: } // end constructor public double taxPayment() { return area*10; } // end method taxPayment} // end class Building

147


Class - Car

public class Car extends Vehical { private int age; private double motorVolume; public Car(int age, double volume) { this.age = age; motorVolume = volume; } // end constructor double taxPayment() { if (age > 15) return 0.0; if(motorVolume ) return ; return ; } // end method taxPayment} // end class Car

148


Class - Truck

public class Truck extends Vehical { private double ton; public Truck(double ton) { this.ton = ton; } // end constructor double taxPayment() { if (ton > 10) return 100.0; return ton*10;} // end method taxPayment} // end class Truck

149


Class - TaxPaymentTest

public class TaxPaymentTest {

public static void main(String[] args) {

Asset[] assets = new Asset[3];//declare and instantiate teh assets array

Asset[0] = new Building(100.0);

Asset[1] = new Car(10,1200.0);

Asset[2] = new Truck(12.0);

double totalTax = 0.0;

for(Asset currentAsset: assets) // calculate total tax due

totalTax += currentAsset.taxPayment();

System.out.printf(“total tax due: %,.2f\n”,totalTax),

} // end main

} // end class TaxPaymentTest

1992-2007 pearson education, inc. all rights reserved. 1 cs01 object-oriented programming: case...

Documents