omai garebel kalkulitar

package j19;
import javax.swing.*;

import java.awt.*;

import java.awt.event.*;

public class j18 {
    public static void main(String[] args) {


    okno nf = new okno();

    }

    }
    class okno extends JFrame {

    private JTextArea text;
    private double p1 = 0, p2 = 0;
    private int oper = 0;

    private void btnClick(JButton btn) {
String str = btn.getText();

if (str=="Выход") System.exit(0);

else if (str=="C")
{
    text.setText(" ");
    p1=p2=0;
}


else if (str=="=")
{
p2 = Integer.parseInt(text.getText());
if (oper==1) text.setText(""+(p1+p2));
if (oper==2) text.setText(""+(p1-p2));
if (oper==3) text.setText(""+(p1*p2));
if (oper==4) text.setText(""+(p1/p2));
}

else if (str=="+") {
oper = 1;
p1 = Double.parseDouble(text.getText());
text.setText("");
}
else if(str=="-")
{
    oper = 2;
    p1 = Double.parseDouble(text.getText());
    text.setText("");
}

else if(str=="*")
{
    oper = 3;
    p1 = Double.parseDouble(text.getText());
    text.setText("");
}

else if(str=="/")
{
    oper = 4;
    p1 = Double.parseDouble(text.getText());
    text.setText("");
}
else
{
    text.setText(""+text.getText()+str);
}









    }

    public okno() {

    Container cont = getContentPane();
    JPanel pan = new JPanel();

    pan.setLayout(null);

    Font btnFont = new Font("serif", 0, 20);

    Font labFont = new Font("arial", 1, 30);

    Font textFont = new Font("arial", 2, 30);


    JButton[] btn1 = new JButton[4];
    for (int i = 0; i < 4; i++) {
    btn1[i] = new JButton();

    btn1[i].setSize(100, 40);

    btn1[i].setFont(btnFont);

    btn1[i].setLocation(150, 50 + i * 50);
    btn1[i].addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e) {
    btnClick((JButton) e.getSource());

    }

    });
    pan.add(btn1[i]);

    }

    JButton[] btn2 = new JButton[4];
    for (int i = 0; i < 4; i++) {
    btn2[i] = new JButton();

    btn2[i].setSize(100, 40);

    btn2[i].setFont(btnFont);

    btn2[i].setLocation(300, 50 + i * 50);
    btn2[i].addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e) {
    btnClick((JButton) e.getSource());

    }

    });
    pan.add(btn2[i]);

    }

    JButton[] btn3 = new JButton[4];
    for (int i = 0; i < 4; i++) {
    btn3[i] = new JButton();

    btn3[i].setSize(100, 40);

    btn3[i].setFont(btnFont);

    btn3[i].setLocation(450, 50 + i * 50);
    btn3[i].addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e) {
    btnClick((JButton) e.getSource());

    }

    });
    pan.add(btn3[i]);

    }

    JButton[] btn4 = new JButton[4];
    for (int i = 0; i < 4; i++) {
    btn4[i] = new JButton();

    btn4[i].setSize(100, 40);

    btn4[i].setFont(btnFont);

    btn4[i].setLocation(600, 50 + i * 50);
    btn4[i].addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e) {
    btnClick((JButton) e.getSource());

    }

    });
    pan.add(btn4[i]);

    }
    JButton btn5 = new JButton();

    btn5 = new JButton();

    btn5.setSize(400, 30);

    btn5.setFont(btnFont);

    btn5.setLocation(225,250);
    btn5.addActionListener(new ActionListener() {
    public void actionPerformed(ActionEvent e) {
    btnClick((JButton) e.getSource());

    }

    });
    pan.add(btn5);






    btn1[0].setText("1");

    btn1[1].setText("4");

    btn1[2].setText("7");

    btn1[3].setText("=");

    btn2[0].setText("2");

    btn2[1].setText("5");

    btn2[2].setText("8");

    btn2[3].setText("0");

    btn3[0].setText("3");

    btn3[1].setText("6");

    btn3[2].setText("9");

    btn3[3].setText("C");

    btn4[0].setText("+");

    btn4[1].setText("-");

    btn4[2].setText("*");

    btn4[3].setText("/");

    btn5.setText("Выход");




    JLabel lab = new JLabel("Результат: ");
    lab.setFont(labFont);
    lab.setBounds(130, 0, 300, 50);
    pan.add(lab);
    text = new JTextArea();

    text.setFont(textFont);

    text.setBounds(300, 10, 300, 35);

    text.setForeground(new Color(0, 0, 100));

    text.setBackground(Color.WHITE);

    pan.add(text);

    cont.add(pan);

    setBounds(0, 0, 800, 600);


    setTitle("Калькулятор");


    setResizable(false);

    setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);


    setVisible(true);

    }

    }