Examples : Java-Eclipse (Simple Calculator)

               At the beginning, you have to create a class named  Calculator  and write source codes to inside this class below


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import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.Arrays;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JTextField;


@SuppressWarnings("serial")
public class Calculator extends JFrame{
private static JButton button1;
private static JButton button2;
private static JButton button3;
private static JButton button4;
private static JButton button5;
private static JButton button6;
private static JButton button7;
private static JButton button8;
private static JButton button9;
private static JButton button0;
private static JButton buttonplus;
private static JButton buttonminus;
private static JButton buttonequal;
private static JButton buttonmultiply;
private static JButton buttondivide;
private static JButton buttonerase;
private static JTextField result;



public Calculator(){

super("CALCULATOR");

setLayout(new FlowLayout(25, 25, 15));

result = new JTextField(16);
add(result);

button1= new JButton("1");

add(button1);

button2= new JButton("2");
add(button2);

button3= new JButton("3");
add(button3);

button4= new JButton("4");
add(button4);

button5= new JButton("5");
add(button5);

button6= new JButton("6");
add(button6);

button7= new JButton("7");
add(button7);

button8= new JButton("8");
add(button8);

button9= new JButton("9");
add(button9);

button0= new JButton("0");
add(button0);

buttonplus= new JButton("+");
add(buttonplus);

buttonminus= new JButton("-");
add(buttonminus);

buttonmultiply= new JButton("*");
add(buttonmultiply);

buttondivide= new JButton(" / ");
add(buttondivide);

buttonequal= new JButton("=");
add(buttonequal);

buttonerase= new JButton("E");
add(buttonerase);






}






public static void main(String args[]){

Calculator screen = new Calculator();
screen.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
screen.setSize(230,310);
screen.setVisible(true);
screen.setResizable(false);


button1.addActionListener(new ActionListener() {

@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
String tut=result.getText();
tut=tut+"1";
result.setText(tut);

}
});


button2.addActionListener(new ActionListener() {

@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
String tut=result.getText();
tut=tut+"2";
result.setText(tut);
}
});

button3.addActionListener(new ActionListener() {

@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
String tut=result.getText();
tut=tut+"3";
result.setText(tut);
}
});

button4.addActionListener(new ActionListener() {
//13543003 ibrahim recep serpici
@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
String tut=result.getText();
tut=tut+"4";
result.setText(tut);
}
});

button5.addActionListener(new ActionListener() {

@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
String tut=result.getText();
tut=tut+"5";
result.setText(tut);
}
});

button6.addActionListener(new ActionListener() {

@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
String tut=result.getText();
tut=tut+"6";
result.setText(tut);
}
});

button7.addActionListener(new ActionListener() {

@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
String tut=result.getText();
tut=tut+"7";
result.setText(tut);
}
});

button8.addActionListener(new ActionListener() {
//13543003 ibrahim recep serpici
@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
String tut=result.getText();
tut=tut+"8";
result.setText(tut);
}
});

button9.addActionListener(new ActionListener() {

@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
String tut=result.getText();
tut=tut+"9";
result.setText(tut);
}
});

button0.addActionListener(new ActionListener() {

@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
String tut=result.getText();
tut=tut+"0";
result.setText(tut);
}
});

buttonplus.addActionListener(new ActionListener() {

@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
String tut=result.getText();
tut=tut+"+";
result.setText(tut);
}
});

buttonminus.addActionListener(new ActionListener() {

@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
String tut=result.getText();
tut=tut+"-";
result.setText(tut);
}
});

buttonmultiply.addActionListener(new ActionListener() {

@Override
public void actionPerformed(ActionEvent arg0) {
// TODO Auto-generated method stub
String tut=result.getText();
tut=tut+"*";
result.setText(tut);
}
});

buttondivide.addActionListener(new ActionListener() {

@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
String tut=result.getText();
tut=tut+"/";
result.setText(tut);
}
});

buttonequal.addActionListener(new ActionListener() {

@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
String holder = result.getText();
ScriptEngineManager manager = new ScriptEngineManager();
ScriptEngine engine = manager.getEngineByName("js");
try {
Object resalt=engine.eval(holder);
result.setText(resalt.toString());

} catch (ScriptException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}

if(result.getText().toString().contains("376")){
JOptionPane.showMessageDialog(null, "This Program written by Ibrahim Recep Serpici");
}
}
});

buttonerase.addActionListener(new ActionListener() {

@Override
public void actionPerformed(ActionEvent e) {
// TODO Auto-generated method stub
String holder = result.getText().toString();
char firstarr[]=holder.toCharArray();

result.setText(String.copyValueOf(Arrays.copyOfRange(firstarr, 0, firstarr.length-1)));



}
});


}

}
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                  After writing this block of code, your application will look like that.