1. Object-Oriented (Component-Based) Program Design Process
CSE 101
Yinong Chen

2. Table of Contents 1 Paradigms of Computing & Languages 2
Design Process of an OO Program 3
Class and Objects from a Class 4
Implement the Solution in C# 5
Interface: Console vs. GUI

3. Granularity of Abstraction
Granularity Level
Programming-in-the-large
Service-Oriented
Programming
Java, C#, VPL
Logic
Programming
e.g. Prolog
Functional
Programming
e.g. LISP/Scheme
Object-Oriented
Programming
C++, Java, C#
Component-Based
Programming
Alice, LabView
C++, Java, C#
Procedural
Programming
Pascal, C
Imperative Programming
Assembly, Algo, FORTRAN
50s
60s
70s
80s
90s
00s
10s
Time
Programming-in-the-small
22 September September 2018

4. Object-Oriented Paradigm
What is a Program?
Program
Algorithm
Data
Data
Process (steps) of data manipulation
Objects of the manipulation
Emphasis:
Imperative /
Procedural Paradigms
Emphasis:
Object-Oriented Paradigm

5. Imperative Paradigm
Fully specified and fully controlled manipulation of named data in a step-wise fashion.
Developed as abstractions of von Neumann machine (stored program concept).
Programs are algorithmic in nature: do this, then that, then repeat this ten times -- focuses on how rather than what.
Why popular
Performance – match the machine
Culture – reading manuals

6. Features of Object-Oriented Programming
Data are organized in Object/Class: Operations are part of an object for manipulating the data in the object;
Abstract data type (class): Encapsulation of state in an object that can only be accessed through operations defined on them. Clean interface -- public and private components.
Inheritance: extending a class by keeping the unchanged parts. Supports code reuse.
Classes are organized in hierarchies.
Dynamic memory allocation and de-allocation
Dynamic binding
Polymorphism

7. Traditional Software Design Process
Software development
What is the need of users
Requirement analysis
What needs to be created to meet the user’s need?
Specification
How to do it?
(Algorithms)
Alternative designs
Implementation (coding)
How to code it?
(programming )
Testing / Evaluation
Run it in a virtual environment
Deployment
Put it in the real environment
22 September September 2018

8. Object-Oriented / Component-Based Software Development
Bricks and Tiles
traditional
Component-
based
22 September September 2018

9. Object-Oriented and Service-Oriented Software Development
Requirement analysis
Programmers
Programmers
Services
development
Object-oriented
development
Problem decomposition
Service
repository
Services
testing
Component
library
Object
testing
Application builder
Application building
Testing
To be discussed later
Deployment

10. Travel Preparation Problem Definition (Requirements)
Input: The numbers of days to travel;
The country name;
The local temperature in Celsius;
Output: The amount of local currency needed
The local temperature in Fahrenheit

11. Problem Decomposition
Main class
Enter numbers of days to travel;
Enter the country name
Make use of other classes to perform computation;
Print output;
days
amount
in USD
Fahrenheit
Celsius
Amount in
local currency
Hotel cost in USD;
Rental car cost in USD;
Meal cost in USD;
Total cost
Convert Celsius to Fahrenheit;
Convert Fahrenheit to Celsius;
amount
in USD
TemperatureConversion class
myCost class
Convert USD amount into local currency amount;
CurrencyConversion class

12. Class Members A class consists of a list of members Each member can be
a data member, or called a variable
a function member, or called a method
Function members
Constructor: is a function member that has the same name as the class name. It is used to
Initialize the data members in the class
Pass values into the class, if the values will be used by multiple function members
Other function members are used
Manipulate data members;
Provide reusable functions for other classes to call;

13. Class versus Objects
A class is a structural design, or a called blueprint
A member can be private or public
private members can be accessed in the class only
Public members can also be accessed outside the class
Static member: If static keyword is used, the member can be accessed without instantiation:
className.memberName
A class can be used to instantiate one or more objects
ClassName refName = new ClassName();
refName.memberName to access the member
A set of library functions (methods) are grouped in one class;
A group of classes are organized as a namespace

14. using System;
class TravelPreparation {
static void Main(string[] args) { // The main method
Console.WriteLine("Please enter the number of days you will travel");
String str = Console.ReadLine(); // read a string of characters
Int32 daysToStay= Convert.ToInt32(str); // Convert string to integer
myCost usdObject = new myCost(daysToStay); // Create an object
int usdCash = usdObject.total(); // Call a method in the object
Console.WriteLine("Please enter the country name you will travel to");
String country = Console.ReadLine();
CurrencyConversion exchange = new CurrencyConversion();
Double AmountLocal = exchange.usdToLocalCurrency(country, usdCash);
Console.WriteLine("The amount of local currency is: " + AmountLocal);
Console.WriteLine("Please enter the temperature in Celsius");
str = Console.ReadLine();
Int32 celsius = Convert.ToInt32(str);
TemperatureConversion c2f = new TemperatureConversion();
Int32 fahrenheit = c2f.getFahrenheit(celsius);
Console.WriteLine("The local temperature in Fahrenheit is: " + fahrenheit); }
Main Class is the class with the Main method

15. TemperatureConversion c2f = new TemperatureConversion();
Class name
Return type
Method name
No constructor
class TemperatureConversion {
public Int32 getFahrenheit(Int32 c)
Double f = c * 9 / ;
return Convert.ToInt32(f); }
public Int32 getCelsius(Int32 f)
Double c = (f - 32) * 5 / 9;
return Convert.ToInt32(c);
Method 1
Parameter passing into function directly
Methods2
TemperatureConversion c2f = new TemperatureConversion();
Int32 fahrenheit = c2f.getFahrenheit(celsius);

16. Reference to an Object
TemperatureConversion c2f = new TemperatureConversion();
Int32 fahrenheit = c2f.getFahrenheit(celsius);
class TemperatureConversion {
public Int32 getFahrenheit(Int32 c)
Double f = c * 9 / ;
return Convert.ToInt32(f); }
public Int32 getCelsius(Int32 f)
Double c = (f - 32) * 5 / 9;
return Convert.ToInt32(c);
42F1D761C
c2f
42F1D761C
c2f.getFahrenheit(23);
c2f. getCelsius(98);

17. class myCost {
private Int32 days;
public myCost(Int32 daysToStay) {
days = daysToStay; }
private Int32 hotel() {
return 100 * days;
private Int32 rentalCar() {
return 30 * days;
private Int32 meals() {
return 20 * days;
public Int32 total() {
return hotel() + rentalCar() + meals();
Constructor: is a method that has the same name as the class.
Allow to pass a value into the class and used by all methods
Data member
The value is provided when an object is created.
myCost usdObject = new myCost(daysToStay);
int usdCash = usdObject.total();

18. class CurrencyConversion {
public Double usdToLocalCurrency(String country, Int32 usdAmount) {
switch(country) {
case "Japan":
return usdAmount * 117;
case "EU":
return usdAmount * 0.71;
case "Hong Kong":
return usdAmount * 7.7;
case "UK":
return usdAmount * 0.49;
case "South Africa":
return usdAmount * 6.8;
default:
return -1; }
This class does not need to have a constructor: It has no data member;
The parameter is passed to the function member, instead of into the class for all member functions to use.
There is one function member only in this class. If there would be more methods and all methods use the same parameters, we would want to pass the parameters into the class, instead of into individual methods.

19. HW 1: Question 1 Anti Block System and Traction Control of a Car
Main class
Get sensor values from Sensors class;
Compare sensor values
Take action by calling Actuator class;
Power level
velocities
Brake force level
Read wheel speed;
Read body Speed;
Control break
Control engine
make
wheelDiameter;
mpg;
tankSize
baseRental
Sensors class
Actuators class
Cars class

20. class Program {
static void Main(string[] args)
Console.WriteLine("Please enter the make of the car");
String make = Console.ReadLine(); // read a string, e.g. bmw
Console.WriteLine("Please enter the miles to drive");
String str = Console.ReadLine(); // read a string, e.g, 1000
Int32 miles = Convert.ToInt32(str);
Cars cRef = new Cars(make); // create an object of Cars
Double cost = cRef.rentalCost(miles);
Console.WriteLine("The cost of driving is " + cost);
Sensors sRef = new Sensors(cRef); // create an object of Sensors
Actuators aRef = new Actuators(); // create an object of Actuators
for (Int32 i = miles; i > 0; i= i - 10) {
Double wv = sRef.wheel_velocity();
Double bv = sRef.body_velocity();
//Console.WriteLine("wv = {0} bv = {1}", wv, bv);
if (Math.Abs(bv - wv) < 1) // 1 is the tolerance
Console.WriteLine("no action");
else if (bv > wv) aRef.brakeForce();
else aRef.enginPower(); }

21. class Cars {
private Double wheelDiameter;
private Double mpg; // miles per galon
private Double tank;
private Double baseRental;
public Double rentalCost(Int32 m) {
return baseRental + (m / mpg) * 3.0; // $3/gal }
public Cars(String make) {
if (make == "bmw") {
wheelDiameter = 17;
mpg = 20; // miles per gallon
tank = 25; // gallons of gasoline
baseRental = 100;
else {
wheelDiameter = 15;
mpg = 24;
baseRental = 50;

22. class Sensors {
private Double wheel_diameter; // inches
Random randomizer;
public Sensors(Cars carRef)
wheel_diameter = carRef.getDiameter();
randomizer = new Random(); }
public Double wheel_velocity() {
Double mile_inch = ; // inches per mile
Double pi = Math.PI;
Double rps = randomizer.Next(25);
Double wv = (pi * wheel_diameter * rps * 3600) / mile_inch;
return wv;
public Double body_velocity() {
Int32 bv = randomizer.Next(70);
return bv;

23. class Actuators {
public void brakeForce()
Console.WriteLine("reduce brake force!"); }
public void enginPower()
Console.WriteLine("reduce engine power level!");

24. Console Interface versus Graphic User Interface