7/31/2019 01 Introduction Object Oriented Programming

1/16

COP-3330: Object Oriented

Programming

Course Introduction

May 14, 2012

Eng. Hector M Lugo-Cordero, MS

7/31/2019 01 Introduction Object Oriented Programming

2/16

Syllabus

Link to syllabus

As of now my webpage will have all material

for the course

http://www.eecs.ucf.edu/~hlugo I will try to get a WebCT session

7/31/2019 01 Introduction Object Oriented Programming

3/16

The Programming World

Couple of programming paradigms exists

Imperative:

Structural: C, FORTRAN

Functional: Scheme, Nodejs

Object Oriented: Objective-C, C++, C#, Java

7/31/2019 01 Introduction Object Oriented Programming

4/16

What is this course about? Developing programs using the object oriented paradigm

Allows abstraction of low level details giving more powerful tools toconcentrate on the higher level tasks

Sentences are composed of Subject, Verb, Predicate or Object

Mary eats the apple Subject: Mary

Verb (action): eats Object: the apple

Object oriented programming is composed of sentences

var.addTo(temp);

Subject (an object): var

Action (method): addTo Object (another object): temp

7/31/2019 01 Introduction Object Oriented Programming

5/16

Problem Solving

1. Understand the problem

2. Dissect the problem into manageable pieces.

3. Design a solution.

4. Consider alternatives to the solution to refineit.

5. Implement the solution.

6. Test the solution and fix any problems thatexist.

7/31/2019 01 Introduction Object Oriented Programming

6/16

History of Java Java was developed in 1995 be James Gosling who works

at Sun Microsystems. Java's ability to execute programs onthe WWW caused an initial buzz.

However, the language has continued to gain in popularitybecause of its object-oriented design. This design is verywell-suited for very large programming projects.

Many academics even feel that Java is an excellent firstprogramming language to learn. Java teaches the conceptof objects very well. Other languages, such as C++, do notreinforce the concept quite as well. Although C++ is good

for learning memory management. Recently Sun was bought by Oracle.

7/31/2019 01 Introduction Object Oriented Programming

7/16

A Java Program1. // Knights.java

2. // Arup Guha

3. // 1/9/074. // A very simple Java program that prints to the screen.

5. public class Knights {

6. /*

7. This is the main function of the program

8. */

9. public static void main(String[] args) {

10. System.out.println("GO KNIGHTS!!!!!!!");11. }

12. }

7/31/2019 01 Introduction Object Oriented Programming

8/16

Understanding the code (comments)

Single line comments are written as shown on

lines 1 4, that is //with some text It is good practice to keep your code clean and

commented such that you may go back to

understand it after some time Lines 1 4 contain the author and some info

about the code, e.g. logs, known bugs, etc.

Multi line comments follow the C conventionof /* anything between this is a comment */,as shown on lines 6 8

7/31/2019 01 Introduction Object Oriented Programming

9/16

Class Definition

Line 5 presents the definition of a class

All java code resides within classes, and each

class must have a name.

In main class the name should be the same filename

We shall go more into classes as the course moves

on

7/31/2019 01 Introduction Object Oriented Programming

10/16

The Main Function

Line 9 presents the main function of a Java

program

It is not necessary to have a main function in

order to have a complete Java Class

For now all classes shall have one

As in C, this is the first function that is called

7/31/2019 01 Introduction Object Oriented Programming

11/16

Understanding Main

There are several keywords on the definition

of main 1) public: access from everywhere

2) static: the method is the same for all instances

of the class 3) void: return type, in this case none

4) String[] args: parameters to main. Equivalent

to Cs int argc, char** argv We shall go more into detail on this

7/31/2019 01 Introduction Object Oriented Programming

12/16

System.out.println

On line 10 we our first line to write something to

the stdout or console in this case

System.out.println works as printf in C, however

it is much simpler to use since it does not require

format specifiers (i.e. %c, %s, %d, %f, etc.)

System.out.printf does exits as well and it is used

just liked in C

Other standard streams include System.in and

System.err

7/31/2019 01 Introduction Object Oriented Programming

13/16

Primitive Data TypesData Type Wrapper Class

byte Byte

short Short

int Integer

long Long

float Float

double Double

boolean Boolean

char Character

void Void

7/31/2019 01 Introduction Object Oriented Programming

14/16

Variable Names

Are case sensitive

Can contain letters, underscores, and numbers

Should not start with numbers

Should be descriptive of the task, they canhave any number of characters

7/31/2019 01 Introduction Object Oriented Programming

15/16

Compilers and Interpreters

Compilers translate code into machine code to

generate a binary file (e.g. .exe)

Interpreters run the code as it reads it

Java is an interpreted language, the JavaVirtual Machine (JVM) runs a .class code

7/31/2019 01 Introduction Object Oriented Programming

16/16

Creating .class files

The command javac may be used as gcc with C to

compile or create .class files which can be runby the JVM

Consider the code Knights.java, to compile it

javac Knights.java The above creates a .class file which may be run

using

java Knights Notice no .class is used (why?)