eduwavepool.unizwa.edu.om€¦ · Web viewJava is a general-purpose; object oriented programming language developed by Sun Microsystems of USA in 1991. Originally called “oak”

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Object Oriented Programming (INFS 222L)

INTRODUCTION

OBJECT ORIENTED PROGRAMMING

OOP Concepts:

The object oriented paradigm is built on the foundation laid by the structured

programming concepts. The fundamental change in OOP is that a program is designed

around the data being operated upon rather upon the operations themselves. Data and

its functions are encapsulated into a single entity. OOP facilitates creating reusable

code that can eventually save a lot of work. A feature called polymorphism permits to

create multiple definitions for operators and functions. Another feature called

inheritance permits to derive new classes from old ones. OOP introduces many new

ideas and involves a different approach to programming than the procedural

programming.

Benefits of object oriented programming:

Data security is enforced.

Inheritance saves time.

User defined data types can be easily constructed.

Inheritance emphasizes inventions of new data types.

Large complexity in the software development can be easily managed.

Basic C++ Knowledge:

C++ began its life in Bell Labs, where Bjarne Stroustrup developed the

language in the early 1980s.

C++ is a powerful and flexible programming language. Thus, with minor

exceptions, C++ is a superset of the C Programming language.



The principal enhancement being the object –oriented concept of a class.

A Class is a user defined type that encapsulates many important mechanisms.

Classes enable programmers to break an application up into small, manageable

pieces, or objects.

Basic concepts of Object oriented programming:

Object:

Objects are the basic run time entities in an object-oriented system. They may

represent a person, a place, a bank account, a table of data or any item that the

program has to handle.

Class:

The entire set of data and code of an object can be made of a user defined data

type with the help of a class.

In fact, Objects are variables of the type class.

Once a class has been defined, we can create any number of objects belonging

to that class. A class is thus a collection of objects of similar type.

for example:

mango, apple, and orange are members of the class fruit.

fruit mango; will create an object mango belonging to the class fruit.

Data Abstraction and Encapsulation:

The wrapping up of data and functions in to a single unit is known as

encapsulation.

Data encapsulation is the most striking feature of a class.

The data is not accessible to the outside world, and only those functions which

are wrapped in the class can access.



This insulation of the data from direct access by the program is called data

hiding.

Abstraction :

Abstraction refers to the act of representing essential features without

including the background details or explanations.

Since the classes use the concept of data abstraction ,thy are known as

abstraction data type(ADT).

Inheritance :

Inheritance is the process by which objects of one class acquire the properties of

objects of another class. Inheritance supports the concept of hierarchical

classification.

for example:



The bird 'robin ' is a part of the class 'flying bird' which is again a part of the

class 'bird'. The concept of inheritance provide the idea of reusability.

Polymorphism:

Polymorphism is another important OOP concept. Polymorphism means the

ability to take more than one form. an operation may exhibit different

instances. The behavior depends upon the types of data used in the operation.

The process of making an operator to exhibit different behaviors in different

instance is known as operator overloading.

Polymorphism plays an important role in allowing objects having different

internal structures to share the same external interface. Polymorphism is

extensively used if implementing inheritance.

The Object-Oriented Approach

The fundamental idea behind object-oriented languages is to combine into a

single program entity both data and the functions that operate on that data. Such an

entity is called an object.

An object's functions, called member functions in C++ (because they belong

to a particular class of objects), typically provide the only way to access its data. If



you want to read a data item in an object, you call a member function in the object. It

will read the item and return the value to you. You can't access the data directly. The

data is hidden, so it is safe from accidental alteration. Data and its functions are said

to be encapsulated into a single entity. Encapsulation and data hiding are key terms in

the description of object-oriented languages.

Java History:

Java is a general-purpose; object oriented programming language developed

by Sun Microsystems of USA in 1991.

Originally called “oak” by James Gosling, one of the inventors if the language.

This goal had a strong impact on the development team to make the language simple,

portable, highly reliable and powerful language.

Java also adds some new features. While C++ is a superset of C. Java is

neither a superset nor a subset of C or C++.



Process of building and running java application programs:

The way these tools are applied to build and run application programs is create

a program. We need create a source code file using a text editor. The source code is

then compiled using the java compiler javac and executed using the java interpreter

java. The java debugger jdb is used to find errors. A complied java program can be

converted into a source code.



1. Write a Simple Java Program to Add Two Numbers

import java.lang.*;import java.io.*;

public class LabOne1 {

public int first; public int second; String name;

public static void main(String [] args) {

LabOne1 lo = new LabOne1(); lo.first=20; lo.second = 10; System.out.println(lo.first+lo.second);

} }



2. Write a Java program to add to numbers dynamically

import java.util.Scanner;


public int first,second; String name;

public static void main(String[]args) {

LabOne2 lo = new LabOne2(); Scanner s = new Scanner(System.in);

System.out.println("Enter First Number:"); lo.first = s.nextInt();

System.out.println("Enter Second Number:"); lo.second = s.nextInt();

System.out.println("Addition of two numbers is:" + (lo.first+lo.second));

}

}



3. Write a Java program to multiply two numbers dynamically



int a,b;



System.out.println("Enter first Number:"); lo.a = s.nextInt();

System.out.println("Enter Second Number:"); lo.b = s.nextInt();

System.out.println("Multiplication is:"+ lo.a*lo.b);

} }



4. Write a Java program to divide two numbers dynamically import java.util.Scanner;


double a,b;



System.out.println("Enter first Number:"); lo.a = s.nextDouble();

System.out.println("Enter Second Number:"); lo.b = s.nextDouble();

System.out.println("Multiplication is:"+ lo.a/lo.b);

} }

OUTPUT:

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5. Write a Dynamic Java Program to display Name




String name; Scanner s = new Scanner(System.in);

System.out.println("Enter your Name: "); name = s.nextLine();

System.out.println("Hello "+name); }

}

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6. Write a Java Program to Print Fibonacci Series?

import java.io.*; import java.util.Scanner; public class Fibonacci { public static void main(String[]args) {

int num,first=0,second=1,i,next;

// To accept data form keyboard Scanner s = new Scanner(System.in); System.out.println("Enter a number"); num = s.nextInt();

for(i=0;i<num;i++) {

if ( i <= 1 ) {

next = i; }else{

next = first + second; first = second; second = next;

} System.out.println(next+" ");

} } }

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7. Write a java program to print n prime numbers? import java.io.*; import java.util.Scanner;

public class PrimeNumber { public static void main(String args[]) { int n, status = 1, num = 3; Scanner in = new Scanner(System.in);

System.out.println("Enter the number of prime numbers you want");

n = in.nextInt();

if (n >= 1) { System.out.println("First "+n+" prime numbers are :-"); System.out.println(2); } for ( int i = 2 ; i <=n ; ) { for ( int j = 2 ; j <= Math.sqrt(num) ; j++ ) { if ( num%j == 0 ) { status = 0; break; } } if ( status != 0 ) { System.out.println(num); i++; } status = 1; num++; } } }

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8. Write a Java Program to Check whether the number is prime or not?

import java.io.*; import java.util.Scanner;

public class PrimeCheck { public static void main(String args[]) { int i, n, flag=0; Scanner s = new Scanner(System.in); System.out.println("Enter a Number: "); n = s.nextInt(); for(i=2;i<=n/2;++i) { if(n%i==0) { flag=1; break; } } if (flag==0) System.out.println(n+"is a prime number."); else System.out.println(n+"is not a prime number."); } }

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9. Write a Java Program to check whether the string is palindrome or not?

import java.io.*; import java.util.Scanner; class Palindrome { public static void main(String args[]) { String original, reverse = ""; Scanner in = new Scanner(System.in);

System.out.println("Enter a string to check if it is a palindrome"); original = in.nextLine();

int length = original.length();

for ( int i = length - 1; i >= 0; i-- )

reverse = reverse + original.charAt(i);

if (original.equals(reverse)) System.out.println("Entered string is a palindrome."); else

System.out.println("Entered string is not a palindrome."); } }

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10. Write a java program for Matrix Multiplication?

import java.io.*; import java.util.Scanner; class MMatrix {

public static void main(String args[]) {

int a[][] = new int [2][2]; int b[][] = new int [2][2]; int c[][] = new int [2][2]; int i,j,k;

Scanner s = new Scanner(System.in); for(i=0;i<b.length;i++) {

for(j=0;j<a.length;j++) {

System.out.println("a["+i+"]["+j+"] ="); a[i][j] = s.nextInt();

} } for(i=0;i<a.length;i++) {

for(j=0;j<b.length;j++) {

System.out.println("b["+i+"]["+j+"] ="); b[i][j] = s.nextInt();

} }

//c[i][j] = 0;

for(i=0;i<c.length;i++) {

for(j=0;j<c.length;j++) {

for(k=0;k<c.length;k++) {

c[i][j] += a[i][k]*b[k][j]; } System.out.print(c[i][j]+" ");

} System.out.println();

} }

}

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11. Write a Java Program for Matrix Addition?


class AMatrix { public static void main(String args[]) { int a[][] = new int [2][2]; int b[][] = new int [2][2]; int c[][] = new int [2][2]; int i,j,k;

Scanner s = new Scanner(System.in); for(i=0;i<b.length;i++) { for(j=0;j<a.length;j++) { System.out.println("a["+i+"]["+j+"] ="); a[i][j] = s.nextInt(); } } for(i=0;i<a.length;i++) { for(j=0;j<b.length;j++) { System.out.println("b["+i+"]["+j+"] ="); b[i][j] = s.nextInt(); } }

//c[i][j] = 0; for(i=0;i<c.length;i++) { for(j=0;j<c.length;j++) { c[i][j] = a[i][j]+b[i][j]; System.out.print(c[i][j]+" "); } System.out.println(); }

}

}

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12. Write a Java Program to perform sum of n Natural numbers using recursive method?


class SNNatural { public static int sumofN(int x) { if(x==0) return x; else return x+sumofN(x-1); } public static void main(String[]args) { int a,b; Scanner s = new Scanner(System.in);

System.out.println("Enter a number: "); a = s.nextInt();

b = sumofN(a); System.out.println(b); }

}

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13. Write a Java Program to demonstrate Constructor Overloading?


class ThisMethodDemo { int a,b;

public ThisMethodDemo() { this(10,20); System.out.println("Constructor without parameters"); }

public ThisMethodDemo(int a, int b) { System.out.println(a+b); }

public static void main(String args[]) { ThisMethodDemo tmd = new ThisMethodDemo(); }

}

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14. Write a java program to demonstrate Garbage Collection?

(GARBAGE COLLECTION)

import java.io.*; import java.lang.*;

public class LabFive1 { public void finalize() { System.out.println("object is garbage collected"); }

public static void main(String [] args) { LabFive1 s1=new LabFive1(); LabFive1 s2=new LabFive1(); s1=null; s2=null;

System.gc(); } }

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15. Write a java program to demonstrate Method Overloading? (METHOD OVERLOADING)

public class LabFive2 { public void sum() { System.out.println("M WO Parmas"); }

public void sum(int a, int b) { System.out.println("M W Parmas"+(a+b)); } public void sum(String x, String y) { System.out.println("M W Parmas"+(x+y)); }


LabFive2 mo = new LabFive2(); mo.sum(); mo.sum(10,20); mo.sum("Hello", "World"); mo = null; System.gc(); } }

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16. Write a Java Program to perform Method Overriding?

(METHOD OVERRIDING) class OverrideDemo { public void show() {

System.out.print("Dell Computer System"); } }

public class LabFive3 extends OverrideDemo { public void show() {

System.out.println("Lenovo Computer System"); super.show();

}


LabFive3 lf = new LabFive3(); lf.show();

}

}

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17. Write a java program to demonstrate This Keyword?

(THIS KEYWORD)

public class LabFive4 { int a,b; public void one(int a, int b) { this.a = a; this.b = b;

System.out.println("a is:"+a + "b is:"+b); } public static void main(String[]args) { LabFive4 td = new LabFive4();

td.one(10,20);

System.out.println(td.a+","+td.b); }

}

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18. Write a Java Program to Demonstrate Inheritance Concept

(Inheritance)


class LabSix22 { public void add(int x, int y) { System.out.println("Addition is: "+(x+y)); }

public void sub(int x, int y) { System.out.println("Subtraction is: "+(x-y)); } } public class LabSix2 extends LabSix22 { public void mul(int x, int y) { System.out.println("Addition is: "+(x*y)); }

public static void main(String[]args) { int a,b;

LabSix2 ls2 = new LabSix2(); Scanner s = new Scanner(System.in);

System.out.println("Enter First number"); a = s.nextInt();

System.out.println("Enter Second number"); b = s.nextInt();

ls2.add(a,b); ls2.sub(a,b); ls2.mul(a,b); } }

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19. Write a Java Program to Demonstrate Inheritance Concept (another)

(Inheritance) class LabSix11 { double amount = 2500.000; public void salary() { System.out.println(amount); } }

//---------end of Class LabSix11-------- class LabSix1 extends LabSix11 { double bonus = 100.000; public void Bonus() { System.out.println(bonus); }

public static void main(String[]args) { LabSix1 ls = new LabSix1();

ls.Bonus(); ls.salary(); } }

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20. Write a Java Program to Demonstrate Data Encapsulation?

(Encapsulation)

class EncapsulationDemo {

private String name; private String idNum; private int age; public int getAge() { return age; } public String getName() { return name; } public String getIdNum() { return idNum; } public void setAge( int newAge) { age = newAge; } public void setName(String newName) { name = newName; }

public void setIdNum( String newId) { idNum = newId; }

} class LabSix3 { public static void main(String args[]) { EncapsulationDemo ed = new EncapsulationDemo (); ed.setName("James"); ed.setAge(20); ed.setIdNum("12343ms"); System.out.print("Name : " + ed.getName() + " Age : " + ed.getAge()); } }

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21. Write a Java Program to demonstrate calling a method passing by value?

(Call by Value)


class Operation {

int data=50; public void change(int data) {

//changes will be in the local variable only

data=data+100; }


Operation op=new Operation();

System.out.println("before change "+op.data); op.change(500);

System.out.println("after change "+op.data); }

}

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22. Write a Java Program to Demonstrate Abstract Class?

(Abstract Class)

abstract class Honda {

public abstract void fuel(); //Abstract Method public abstract void engine();//Abstract Method public void ac()//Concrete Method {

System.out.println("Air conditioning is optional");

} }

public class LabSeven1 extends Honda {

@Override public void fuel() {

System.out.println("Must to use fuel"); }

@Override public void engine() {

System.out.println("Must to have brakes"); } public static void main(String args[]) {

LabSeven1 c = new LabSeven1(); c.fuel(); c.engine(); c.ac();

} }

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23. Write a Java Program to Demonstrate Polymorphism?

(Dynamic Polymorphism)

class Bird {

public void eat() {

System.out.println("All Birds eat");

} } class Hen extends Bird {

@Override public void eat() {

System.out.println("Hen eats Grains"); }

} class Eagle extends Bird {


System.out.println("Eagle eats Worms"); }

} public class LabSeven2 {


Bird b = new Bird(); b.eat(); Eagle e = new Eagle(); b = e; b.eat();

Hen h = new Hen(); b = h; b.eat();

} }

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24. Write a Java Program to Demonstrate Interface or Multiple Inheritance?

(Interface) interface Birds {

public abstract void eat(); } class Vulture implements Birds {

@Override public void eat() { System.out.println("Vulture eats Flesh"); }

}

class Crane implements Birds {


System.out.println("Crane eats Fish"); }

}

public class LabSeven3 {


Birds b; Crane c = new Crane(); b = c; b.eat(); Vulture v = new Vulture(); b = v; b.eat();

} }

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25. Write a Java Program to Demonstrate Both Extends and Implements? (Using Class, Abstract Class and Interface)

interface Hello1 // 1st interface { public abstract void display1(); } interface Hello2 // 2nd interface { public abstract void display2(); } class Test1 // concrete (non-abstract) class {

public void calculate() {

System.out.println("Concrete class Test1 method calculate() executed"); } }abstract class Test2 extends Test1 // abstract class extending Test1 { public abstract void show(); } public class LabSeven4 extends Test2 implements Hello1, Hello2 {

@Override public void display1() {

System.out.println("Interface Hello1 method display1() executed"); }

@Override public void display2() {

System.out.println("Interface Hello2 method display2() executed"); }

@Override public void show() {

System.out.println("Abstract class Test2 method show() executed"); }

public static void main(String []args) {

LabSeven4 d1 = new LabSeven4();

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d1.display1(); d1.display2(); d1.calculate(); d1.show();

} } 26. Write a Java Program to demonstrate how exception

terminates java program?


public class MyException {


int a=10;

int b=0; System.out.println(a/b); System.out.println("End of Program");

} }

27. Write a Java Program to Handle Exceptions using try-catch

blocks?

import java.io.*; import java.lang.*; public class MyExceptionHandle {


int a=10;

int b=0;

try{ System.out.println(a/b);

} catch(Exception ex){

System.out.println("Exception Message: "+ex.getMessage());

}

32



System.out.println("After for loop..."); }

}

33



28. Write a Java Program to handle exceptions using Nested-try blocks?

import java.lang.*; import java.io.*; class NestedTry {


//Parent try block try{

//Child try block1 try{

System.out.println("Inside block1"); int b =45/0; System.out.println(b);

}catch(ArithmeticException e1){

System.out.println("Exception: e1"); }

System.out.println("Just other statement");

}catch(ArithmeticException e3){

System.out.println("Arithmetic Exception");

System.out.println("Inside parent try catch block"); } System.out.println("Next statement..");

} }

34



29. Write a java program to handle exception using try, catch and finally blocks?

import java.lang.*; import java.io.*;

class TestExceptions {

static void myMethod(int testnum) throws Exception {

System.out.println ("start - myMethod"); if (testnum == 12)

throw new Exception();

System.out.println("end - myMethod"); return;

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

int testnum = 12; try {

System.out.println("try - first statement"); myMethod(testnum); System.out.println("try - last statement");

} catch (Exception ex) {

System.out.println("An Exception"); } finally {

System. out. println("finally") ; } System.out.println("Out of try/catch/finally - statement");

} }

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30. Write a Java Program to Handle Exception using throw keyword?


public class ThrowExample {

static void checkEligibilty(int stuage, int stuweight) {

if(stuage<12 && stuweight<40) {

throw new ArithmeticException("Student is not");

}else {

System.out.println("Entries Valid!!"); }

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

System.out.println("Welcome to the Registration process!!");

checkEligibilty(10, 39); System.out.println("Have a nice day..");

} }

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31. Write a java program to handle check and unchecked exceptions?

(Or)32. Write a java program to demonstrate exception handling

using Throws keyword?

import java.io.*;

class Example {

public static void main(String args[]) throws IOException {

FileInputStream fis = null;

/*This constructor FileInputStream(File filename) * throws FileNotFoundException which is a checked * exception*/

fis = new FileInputStream("D:/myfile.txt"); int k;

/*Method read() of FileInputStream class also throws * a checked exception: IOException*/

while(( k = fis.read() ) != -1) {

System.out.print((char)k); }

/*The method close() closes the file input stream * It throws IOException*/

fis.close(); }

}

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33. Write a Java Program to simple Applet?

import java.awt.*; import java.applet.*;

public class AppletDemo extends Applet {

public void init() {

System.out.println("init(): Initiated"); } public void start() {

System.out.println("start(): Started"); } public void paint(Graphics g) {

System.out.println("paint(): Running"); } public void stop() {

System.out.println("stop(): Stopped"); } public void destroy() {

System.out.println"destroy():Destroyed"); }

}

HTML FILE

<applet code="AppletDemo.class" height=450 width=450> </applet>

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34. Write a Java Program to display an image in Applet?

import java.applet.*; import java.awt.*;

public class AppletImage extends Applet {

Image img; public void init() {

System.out.println("init(): Initiated"); }

public void start() {

System.out.println("start(): Started"); }

public void paint(Graphics g) {

img = getImage(getCodeBase(), "Ammi 1.jpg"); g.drawImage(img, 0, 0, this);

} public void stop() {


System.out.println"destroy():Destroyed"); }

} HTML FILE

<applet code="AppletImage.class" height=450 width=450> </applet>

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35. Write a Java Program to demonstrate parameterized Applet?


public class AppletParam extends Applet {


System.out.println("init(): Initiated"); }

public void start() {

System.out.println("start(): Started"); } public void paint(Graphics g) {

String myfont = getParameter("font"); int mysize =Integer.parseInt( getParameter("size")); String mystring = getParameter("string"); int mystyle= Integer.parseInt(getParameter("style")); Font f = new Font(myfont,mystyle,mysize); g.setColor(Color.red); g.drawString(mystring,100,100);System.out.println("paint(): Running");

} public void stop() {


System.out.println("destroy(): Destroyed"); }

}

HTML FILE <applet code="AppletParam.class" height=450 width=450> <param name="Font" value="Arial"> <param name="size" value="45"> <param name="string" value="My Applets!!">

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<param name="style" value="15"> </applet>

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36. Write a Java Program to set Foreground and Background

Color using Applet?


public class AppletColor extends Applet {


System.out.println("init(): Initiated"); } public void start() {

System.out.println("start(): Started"); }

public void paint(Graphics g) {

setForeground(Color.white); setBackground(Color.black); g.drawString(“Welecome”,150,150);

}

public void stop() {


System.out.println("destroy(): Destroyed"); }

} HTML FILE <applet code="AppletColor.class" height=450 width=450> </applet>

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Event Handling and AWT 37. Write a Java Program to Handle Mouse Events?

import java.awt.*; import java.awt.event.*; import java.applet.*;

public class EHAppletDemo extends Applet implements MouseListener {


addMouseListener(this); } public void mouseClicked(MouseEvent me) {

setBackground(Color.red); } public void mouseEntered(MouseEvent me) {

setBackground(Color.green); } public void mouseReleased(MouseEvent me){

setBackground(Color.blue); } public void mouseExited(MouseEvent me){

setBackground(Color.black); } public void mousePressed(MouseEvent me) {

setBackground(Color.yellow); }

} HTML FILE

<applet code="EHAppletDemo.class" height=450 width=450> </applet>

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38. Write a Java Program to Handle Key Board Key Events?

import java.awt.*; import java.awt.event.*; import java.applet.*;

public class EHAppletKey extends Applet implements KeyListener {


addKeyListener(this); }

public void keyReleased(KeyEvent ke){

setBackground(Color.black); }

public void keyTyped(KeyEvent ke){

setBackground(Color.blue); }

public void keyPressed(KeyEvent ke) {

setBackground(Color.yellow); }

} HTML FILE

<applet code="EHAppletKey.class" height=450 width=450> </applet>

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39. Write a Java Program to Handle AWT Button Events?

import java.applet.*; import java.awt.event.*; import java.awt.*;

public class ButtonDemo extends Applet implements ActionListener {

String message = ""; public void init() {

Button b1 = new Button("Red"); Button b2 = new Button("Blue"); Button b3 = new Button("Green"); add(b1); add(b2); add(b3); b1.addActionListener(this); b2.addActionListener(this); b3.addActionListener(this);

} public void actionPerformed(ActionEvent ae) {

message = ae.getActionCommand(); if(message == "Red") {

setBackground(Color.red); }else if(message == "Blue") {

setBackground(Color.blue); } else if(message == "Green") {

setBackground(Color.green); } message = "Your Clicked "+message+" button";

} public void paint(Graphics g) {

g.drawString(message,150,150); }

}

HTML FILE

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<applet code="ButtonDemo.class" height=450 width=450> </applet>

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40. Write a Java Program to demonstrate AWT TextField, AWT Label and to Handle AWT Choice Events?

import java.applet.*; import java.awt.event.*; import java.awt.*;

public class ChoiceDemo extends Applet implements ItemListener {

String message = "";

Choice country = new Choice(); TextField tf = new TextField(); public void init() {

country.add("Oman"); country.add("UAE"); country.add("KSA"); country.add("Bahrain"); country.add("Qatar"); country.add("Kuwait"); Label l1 = new Label("Select Country"); add(l1); add(country);add(tf); tf.setColumns(20); country.addItemListener(this);

} public void itemStateChanged(ItemEvent ie) {

message = country.getSelectedItem(); tf.setText(message); repaint();

} public void paint(Graphics g) {

g.drawString(message,150,150); }

} HTML FILE <applet code="ChoiceDemo.class" height=450 width=450> </applet>

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Documents

eduwavepool.unizwa.edu.om€¦ · Web viewJava is a general-purpose; object oriented programming language developed by Sun Microsystems of USA in 1991. Originally called “oak”