Difference between C and C++

on 11:15 AM

  • C does not have any classes or objects. It is procedure and function driven. There is no concept of access through objects and structures are the only place where there is a access through a compacted variable. c++ is object oriented.
  • C structures have a different behaviour compared to c++ structures. Structures in c do not accept functions as their parts.
  • C input/output is based on library and the processes are carried out by including functions. C++ i/o is made through console commands cin and cout.
  • C functions do not support overloading. Operator overloading is a process in which the same function has two or more different behaviours based on the data input by the user.
  • C does not support new or delete commands. The memory operations to free or allocate memory in c are carried out by malloc() and free().
  • Undeclared functions in c++ are not allowed. The function has to have a prototype defined before the main() before use in c++ although in c the functions can be declared at the point of use.
  • After declaring structures and enumerators in c we cannot declare the variable for the structure right after the end of the structure as in c++.
  • For an int main() in c++ we may not write a return statement but the return is mandatory in c if we are using int main().
  • In C++ identifiers are not allowed to contain two or more consecutive underscores in any position. C identifiers cannot start with two or more consecutive underscores, but may contain them in other positions.
  • C has a top down approach whereas c++ has a bottom up approach.
  • In c a character constant is automatically elevated to an integer whereas in c++ this is not the case.
  • In c declaring the global variable several times is allowed but this is not allowed in c++.

How To Remove Virus Without Using Antivirus Program -- HAMEED.

on 5:09 AM

Creating a basic program in java

on 10:30 AM

Virus Removal Process

on 12:00 PM

Simple Java Program for Beginners

on 11:20 PM

Hello World Java

Simple Java Program for beginners (The HelloWorld.java)

Java is powerful programming language and it is used to develop robust applications. Writing a simple Hello World program is stepwise step. This short example shows how to write first java application and compile and run it. I am assuming that latest version of JDK is installed on your machine

HelloWorld.java - the source code for the "Hello, world!" program

class HelloWorld {
public static void main(String[] args)
{
System.out.println("Hello World!");
}
}

How to save
To run this program, save it in a file with the name HelloWorld.java. It must be sure that the file name must match the name of the class.

Compile the program

javac HelloWorld.java command is used to compile the source code.
When you compile the program you'll create a byte-code file named HelloWorld.class.
You can confirm this with the dir command in the DOS/Windows world.

Execute the byte code
Now you can execute the byte code in the Java interpreter with this command:
java HelloWorld

Output of the program
When you run the program at the command line, you'll see this output
Hello, world!

Understanding the HelloWorld.java code
Let's examine the HelloWorld.java file. Class is the basic building block of the java program, java codes are written in the java class.

class HelloWorld{

//Java Codes

}

Java codes are saved in the same name as the class name.java, so we have saved the file with the name "HelloWorld.java".

There is one method public static void main (String[] args) which is necessary to for any class to be runnable. This function is the entry point of the execution. And the code System.out.println("Hello World!"); actually writes the Hello World! on the screen

.Net Tutorial - How to Install .NET on new Windows 7

on 11:00 PM

How to download and install Java JDK

on 10:55 PM

A Must watch for JAVA Beginner


.NET

on 12:04 PM

.NET

Microsoft's .NET CLI executable environment, and some of the corresponding class library, have been standardized and can be freely implemented without a license. A few standards-compliant free software environments have been implemented, such as the Mono Project and DotGNU. The Mono Project has also implemented many of Microsoft's non-standard libraries by examining Microsoft materials, similar to GNU Classpath and Java.

Microsoft is currently distributing a shared source version of its .NET runtime environment for academic use, however it is only supported on Windows 7 and has not been updated after .NET 4.0.[7]

The Mono project aims to avoid infringing on any patents or copyrights, and to the extent that they are successful, the project can be safely distributed and used under the GPL. On November 2, 2006, Microsoft and Novell announced a joint agreement whereby Microsoft promised not to sue Novell or its customers for patent infringement.[8] According to a statement on the blog of Mono project leader Miguel de Icaza, this agreement only extends to Mono for Novell developers and users.[9] Because of the possible threat of Microsoft patents, the FSF recommends that people avoid creating software that depends on Mono or C#.[10][11]

The Microsoft/Novell agreement was criticized by some in the open source community because it violates the principles of giving equal rights to all users of a particular program (see Agreement with Microsoft and Mono and Microsoft's patents).

JAVA

on 12:03 PM

Java

The primary implementation of the Java platform is available as an Open Source implementation called OpenJDK.

While "Java" is an Oracle trademark, and only Oracle can license the name "Java", numerous free software projects exist that are compatible with Oracle Java. Most notably, GNU Classpath and GCJ provide a free software class library and a compiler that are partially compatible with the current version of OracleJava.[1] Sun announced on November 13, 2006 that all Java source code, excluding closed-source code for which they do not retain rights, will be released under a modified version of the GPL,[2] and released two fundamental parts of the JRE and JDK: HotSpot and the javac compiler under the GPL.[3][4]

Following their promise, Sun released the complete source code of the Class library under GPL on May 8, 2007, except some limited parts that were licensed by Sun from 3rd parties who did not want their code to be released under an open-source license[5] (see also Free Java implementations). Sun's goal is to replace the parts that remain closed with alternative implementations and make the class library completely open.

In June 2008, Red Hat announced[6] that the IcedTea project has passed the rigorous Java TCK, indicating a fully functional open-source implementation of the Java platform.

CALCULATOR by USENG JAVA

on 1:11 PM

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Container;
import java.awt.FlowLayout;
import java.awt.Font;
import java.awt.GridLayout;
import java.awt.Window;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;

import javax.swing.JButton;
import javax.swing.JDialog;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.KeyStroke;

public class Calculator extends JFrame implements ActionListener{
// Variables
final int MAX_INPUT_LENGTH = 20;
final int INPUT_MODE = 0;
final int RESULT_MODE = 1;
final int ERROR_MODE = 2;
int displayMode;

boolean clearOnNextDigit, percent;
double lastNumber;
String lastOperator;

private JMenu jmenuFile, jmenuHelp;
private JMenuItem jmenuitemExit, jmenuitemAbout;

private JLabel jlbOutput;
private JButton jbnButtons[];
private JPanel jplMaster, jplBackSpace, jplControl;

/*
* Font(String name, int style, int size)
Creates a new Font from the specified name, style and point size.
*/

Font f12 = new Font("Times New Roman", 0, 12);
Font f121 = new Font("Times New Roman", 1, 12);

// Constructor
public Calculator()
{
/* Set Up the JMenuBar.
* Have Provided All JMenu's with Mnemonics
* Have Provided some JMenuItem components with Keyboard Accelerators
*/

jmenuFile = new JMenu("File");
jmenuFile.setFont(f121);
jmenuFile.setMnemonic(KeyEvent.VK_F);

jmenuitemExit = new JMenuItem("Exit");
jmenuitemExit.setFont(f12);
jmenuitemExit.setAccelerator(KeyStroke.getKeyStroke( KeyEvent.VK_X,
ActionEvent.CTRL_MASK));
jmenuFile.add(jmenuitemExit);

jmenuHelp = new JMenu("Help");
jmenuHelp.setFont(f121);
jmenuHelp.setMnemonic(KeyEvent.VK_H);

jmenuitemAbout = new JMenuItem("About Calculator");
jmenuitemAbout.setFont(f12);
jmenuHelp.add(jmenuitemAbout);

JMenuBar mb = new JMenuBar();
mb.add(jmenuFile);
mb.add(jmenuHelp);
setJMenuBar(mb);

//Set frame layout manager

setBackground(Color.gray);

jplMaster = new JPanel();

jlbOutput = new JLabel("0");
jlbOutput.setHorizontalTextPosition(JLabel.RIGHT);
jlbOutput.setBackground(Color.WHITE);
jlbOutput.setOpaque(true);

// Add components to frame
getContentPane().add(jlbOutput, BorderLayout.NORTH);

jbnButtons = new JButton[23];
// GridLayout(int rows, int cols, int hgap, int vgap)

JPanel jplButtons = new JPanel(); // container for Jbuttons

// Create numeric Jbuttons
for (int i=0; i<=9; i++)
{
// set each Jbutton label to the value of index
jbnButtons[i] = new JButton(String.valueOf(i));
}

// Create operator Jbuttons
jbnButtons[10] = new JButton("+/-");
jbnButtons[11] = new JButton(".");
jbnButtons[12] = new JButton("=");
jbnButtons[13] = new JButton("/");
jbnButtons[14] = new JButton("*");
jbnButtons[15] = new JButton("-");
jbnButtons[16] = new JButton("+");
jbnButtons[17] = new JButton("sqrt");
jbnButtons[18] = new JButton("1/x");
jbnButtons[19] = new JButton("%");

jplBackSpace = new JPanel();
jplBackSpace.setLayout(new GridLayout(1, 1, 2, 2));

jbnButtons[20] = new JButton("Backspace");
jplBackSpace.add(jbnButtons[20]);

jplControl = new JPanel();
jplControl.setLayout(new GridLayout(1, 2, 2 ,2));

jbnButtons[21] = new JButton(" CE ");
jbnButtons[22] = new JButton("C");

jplControl.add(jbnButtons[21]);
jplControl.add(jbnButtons[22]);

// Setting all Numbered JButton's to Blue. The rest to Red
for (int i=0; i jbnButtons[i].setFont(f12);

if (i<10)
jbnButtons[i].setForeground(Color.blue);

else
jbnButtons[i].setForeground(Color.red);
}

// Set panel layout manager for a 4 by 5 grid
jplButtons.setLayout(new GridLayout(4, 5, 2, 2));

//Add buttons to keypad panel starting at top left
// First row
for(int i=7; i<=9; i++) {
jplButtons.add(jbnButtons[i]);
}

// add button / and sqrt
jplButtons.add(jbnButtons[13]);
jplButtons.add(jbnButtons[17]);

// Second row
for(int i=4; i<=6; i++)
{
jplButtons.add(jbnButtons[i]);
}

// add button * and x^2
jplButtons.add(jbnButtons[14]);
jplButtons.add(jbnButtons[18]);

// Third row
for( int i=1; i<=3; i++)
{
jplButtons.add(jbnButtons[i]);
}

//adds button - and %
jplButtons.add(jbnButtons[15]);
jplButtons.add(jbnButtons[19]);

//Fourth Row
// add 0, +/-, ., +, and =
jplButtons.add(jbnButtons[0]);
jplButtons.add(jbnButtons[10]);
jplButtons.add(jbnButtons[11]);
jplButtons.add(jbnButtons[16]);
jplButtons.add(jbnButtons[12]);

jplMaster.setLayout(new BorderLayout());
jplMaster.add(jplBackSpace, BorderLayout.WEST);
jplMaster.add(jplControl, BorderLayout.EAST);
jplMaster.add(jplButtons, BorderLayout.SOUTH);

// Add components to frame
getContentPane().add(jplMaster, BorderLayout.SOUTH);
requestFocus();

//activate ActionListener
for (int i=0; i jbnButtons[i].addActionListener(this);
}

jmenuitemAbout.addActionListener(this);
jmenuitemExit.addActionListener(this);

clearAll();

//add WindowListener for closing frame and ending program
addWindowListener(new WindowAdapter() {

public void windowClosed(WindowEvent e)
{
System.exit(0);
}
}
);
} //End of Contructor Calculator

// Perform action
public void actionPerformed(ActionEvent e){
double result = 0;

if(e.getSource() == jmenuitemAbout){
JDialog dlgAbout = new CustomABOUTDialog(this,
"About Java Swing Calculator", true);
dlgAbout.setVisible(true);
}else if(e.getSource() == jmenuitemExit){
System.exit(0);
}

// Search for the button pressed until end of array or key found
for (int i=0; i {
if(e.getSource() == jbnButtons[i])
{
switch(i)
{
case 0:
addDigitToDisplay(i);
break;

case 1:
addDigitToDisplay(i);
break;

case 2:
addDigitToDisplay(i);
break;

case 3:
addDigitToDisplay(i);
break;

case 4:
addDigitToDisplay(i);
break;

case 5:
addDigitToDisplay(i);
break;

case 6:
addDigitToDisplay(i);
break;

case 7:
addDigitToDisplay(i);
break;

case 8:
addDigitToDisplay(i);
break;

case 9:
addDigitToDisplay(i);
break;

case 10: // +/-
processSignChange();
break;

case 11: // decimal point
addDecimalPoint();
break;

case 12: // =
processEquals();
break;

case 13: // divide
processOperator("/");
break;

case 14: // *
processOperator("*");
break;

case 15: // -
processOperator("-");
break;

case 16: // +
processOperator("+");
break;

case 17: // sqrt
if (displayMode != ERROR_MODE)
{
try
{
if (getDisplayString().indexOf("-") == 0)
displayError("Invalid input for function!");

result = Math.sqrt(getNumberInDisplay());
displayResult(result);
}

catch(Exception ex)
{
displayError("Invalid input for function!");
displayMode = ERROR_MODE;
}
}
break;

case 18: // 1/x
if (displayMode != ERROR_MODE){
try
{
if (getNumberInDisplay() == 0)
displayError("Cannot divide by zero!");

result = 1 / getNumberInDisplay();
displayResult(result);
}

catch(Exception ex) {
displayError("Cannot divide by zero!");
displayMode = ERROR_MODE;
}
}
break;

case 19: // %
if (displayMode != ERROR_MODE){
try {
result = getNumberInDisplay() / 100;
displayResult(result);
}

catch(Exception ex) {
displayError("Invalid input for function!");
displayMode = ERROR_MODE;
}
}
break;

case 20: // backspace
if (displayMode != ERROR_MODE){
setDisplayString(getDisplayString().substring(0,
getDisplayString().length() - 1));

if (getDisplayString().length() < 1)
setDisplayString("0");
}
break;

case 21: // CE
clearExisting();
break;

case 22: // C
clearAll();
break;
}
}
}
}

void setDisplayString(String s){
jlbOutput.setText(s);
}

String getDisplayString (){
return jlbOutput.getText();
}

void addDigitToDisplay(int digit){
if (clearOnNextDigit)
setDisplayString("");

String inputString = getDisplayString();

if (inputString.indexOf("0") == 0){
inputString = inputString.substring(1);
}

if ((!inputString.equals("0") || digit > 0)
&& inputString.length() < MAX_INPUT_LENGTH){
setDisplayString(inputString + digit);
}


displayMode = INPUT_MODE;
clearOnNextDigit = false;
}

void addDecimalPoint(){
displayMode = INPUT_MODE;

if (clearOnNextDigit)
setDisplayString("");

String inputString = getDisplayString();

// If the input string already contains a decimal point, don't
// do anything to it.
if (inputString.indexOf(".") < 0)
setDisplayString(new String(inputString + "."));
}

void processSignChange(){
if (displayMode == INPUT_MODE)
{
String input = getDisplayString();

if (input.length() > 0 && !input.equals("0"))
{
if (input.indexOf("-") == 0)
setDisplayString(input.substring(1));

else
setDisplayString("-" + input);
}

}

else if (displayMode == RESULT_MODE)
{
double numberInDisplay = getNumberInDisplay();

if (numberInDisplay != 0)
displayResult(-numberInDisplay);
}
}

void clearAll() {
setDisplayString("0");
lastOperator = "0";
lastNumber = 0;
displayMode = INPUT_MODE;
clearOnNextDigit = true;
}

void clearExisting(){
setDisplayString("0");
clearOnNextDigit = true;
displayMode = INPUT_MODE;
}

double getNumberInDisplay() {
String input = jlbOutput.getText();
return Double.parseDouble(input);
}

void processOperator(String op) {
if (displayMode != ERROR_MODE)
{
double numberInDisplay = getNumberInDisplay();

if (!lastOperator.equals("0"))
{
try
{
double result = processLastOperator();
displayResult(result);
lastNumber = result;
}

catch (DivideByZeroException e)
{
}
}

else
{
lastNumber = numberInDisplay;
}

clearOnNextDigit = true;
lastOperator = op;
}
}

void processEquals(){
double result = 0;

if (displayMode != ERROR_MODE){
try
{
result = processLastOperator();
displayResult(result);
}

catch (DivideByZeroException e) {
displayError("Cannot divide by zero!");
}

lastOperator = "0";
}
}

double processLastOperator() throws DivideByZeroException {
double result = 0;
double numberInDisplay = getNumberInDisplay();

if (lastOperator.equals("/"))
{
if (numberInDisplay == 0)
throw (new DivideByZeroException());

result = lastNumber / numberInDisplay;
}

if (lastOperator.equals("*"))
result = lastNumber * numberInDisplay;

if (lastOperator.equals("-"))
result = lastNumber - numberInDisplay;

if (lastOperator.equals("+"))
result = lastNumber + numberInDisplay;

return result;
}

void displayResult(double result){
setDisplayString(Double.toString(result));
lastNumber = result;
displayMode = RESULT_MODE;
clearOnNextDigit = true;
}

void displayError(String errorMessage){
setDisplayString(errorMessage);
lastNumber = 0;
displayMode = ERROR_MODE;
clearOnNextDigit = true;
}

public static void main(String args[]) {
Calculator calci = new Calculator();
Container contentPane = calci.getContentPane();
// contentPane.setLayout(new BorderLayout());
calci.setTitle("Java Swing Calculator");
calci.setSize(241, 217);
calci.pack();
calci.setLocation(400, 250);
calci.setVisible(true);
calci.setResizable(false);
}

} //End of Swing Calculator Class.

class DivideByZeroException extends Exception{
public DivideByZeroException()
{
super();
}

public DivideByZeroException(String s)
{
super(s);
}
}

class CustomABOUTDialog extends JDialog implements ActionListener {
JButton jbnOk;

CustomABOUTDialog(JFrame parent, String title, boolean modal){
super(parent, title, modal);
setBackground(Color.black);

JPanel p1 = new JPanel(new FlowLayout(FlowLayout.CENTER));

StringBuffer text = new StringBuffer();
text.append("Calculator Information\n\n");
text.append("Developer: Hemanth\n");
text.append("Version: 1.0");

JTextArea jtAreaAbout = new JTextArea(5, 21);
jtAreaAbout.setText(text.toString());
jtAreaAbout.setFont(new Font("Times New Roman", 1, 13));
jtAreaAbout.setEditable(false);

p1.add(jtAreaAbout);
p1.setBackground(Color.red);
getContentPane().add(p1, BorderLayout.CENTER);

JPanel p2 = new JPanel(new FlowLayout(FlowLayout.CENTER));
jbnOk = new JButton(" OK ");
jbnOk.addActionListener(this);

p2.add(jbnOk);
getContentPane().add(p2, BorderLayout.SOUTH);

setLocation(408, 270);
setResizable(false);

addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e)
{
Window aboutDialog = e.getWindow();
aboutDialog.dispose();
}
}
);

pack();
}

public void actionPerformed(ActionEvent e)
{
if(e.getSource() == jbnOk) {
this.dispose();
}
}

}


JDBC program

on 1:45 PM

Appendix B: Example JDBC Programs

B.1 Using SELECT

import java.net.URL;
import java.sql.*;

class Select {

public static void main(String argv[]) {
try {
// Create a URL specifying an ODBC data source name.
String url = "jdbc:odbc:wombat";

// Connect to the database at that URL.
Connection con = DriverManager.getConnection(url, "kgh", "");

// Execute a SELECT statement
Statement stmt = con.createStatement();
ResultSet rs = stmt.executeQuery("SELECT a, b, c, d, key FROM Table1");

// Step through the result rows.
System.out.println("Got results:");
while (rs.next()) {
// get the values from the current row:
int a = rs.getInt(1);
BigDecimal b = rs.getBigDecimal(2);
char c[] = rs.getString(3).tocharArray();
boolean d = rs.getBoolean(4);
String key = rs.getString(5);

// Now print out the results:
System.out.print(" key=" + key);
System.out.print(" a=" + a);
System.out.print(" b=" + b);
System.out.print(" c=");
for (int i = 0; i < c.length; i++) {
System.out.print(c[i]);
}
System.out.print(" d=" + d);
System.out.print("\n");
}

stmt.close();
con.close();
} catch (java.lang.Exception ex) {
ex.printStackTrace();
}
}
}

B.2 Using UPDATE


// Update a couple of rows in a database.

import java.net.URL;
import java.sql.*;

class Update {

public static void main(String argv[]) {
try {
// Create a URL specifying an ODBC data source name.
String url = "jdbc:odbc:wombat";

// Connect to the database at that URL.
Connection con = DriverManager.getConnection(url, "kgh", "");

// Create a prepared statement to update the "a" field of a
// row in the "Table1" table.
// The prepared statement takes two parameters.
PreparedStatement stmt = con.prepareStatement(
"UPDATE Table1 SET a = ? WHERE key = ?");

// First use the prepared statement to update
// the "count" row to 34.
stmt.setInt(1, 34);
stmt.setString(2, "count");
stmt.executeUpdate();
System.out.println("Updated \"count\" row OK.");

// Now use the same prepared statement to update the
// "mirror" field.
// We rebind parameter 2, but reuse the other parameter.
stmt.setString(2, "mirror");
stmt.executeUpdate();
System.out.println("Updated \"mirror\" row OK.");

stmt.close();
con.close();

} catch (java.lang.Exception ex) {
ex.printStackTrace();
}
}
}