AWT Calculator 2.0

/**
 * AWT Calculator 2.0
 * Date : 13.08.19
 */
package AWT;
import java.awt.*;
import java.awt.event.*;

public class Calculator2 implements ActionListener {
    TextField tf;
    Button b0, b1, b2, b3, b4, b5, b6, b7, b8, b9;
    Button plus, minus, mult, div, equal, point;
    int choice = 0;
    //int operation = 0;
    double dis = 0, temp = 0;
    Calculator2(){
        Frame f = new Frame("Calculator");
        f.setSize(400,400);
        f.setLayout(null);
        f.setVisible(true);

        tf = new TextField("0");
        tf.setBounds(50, 50, 300, 50);
        tf.setEditable(false);
        f.add(tf);

        b7 = new Button("7");
        b7.setBounds(80, 110, 50, 50);
        b7.addActionListener(this);
        f.add(b7);

        b8 = new Button("8");
        b8.setBounds(140, 110, 50, 50);
        b8.addActionListener(this);
        f.add(b8);

        b9 = new Button("9");
        b9.setBounds(200, 110, 50, 50);
        b9.addActionListener(this);
        f.add(b9);

        div = new Button("/");
        div.setBounds(260, 110, 50, 50);
        div.addActionListener(this);
        f.add(div);

        b4 = new Button("4");
        b4.setBounds(80, 170, 50, 50);
        b4.addActionListener(this);
        f.add(b4);

        b5 = new Button("5");
        b5.setBounds(140, 170, 50, 50);
        b5.addActionListener(this);
        f.add(b5);

        b6 = new Button("6");
        b6.setBounds(200, 170, 50, 50);
        b6.addActionListener(this);
        f.add(b6);

        mult = new Button("X");
        mult.setBounds(260, 170, 50, 50);
        mult.addActionListener(this);
        f.add(mult);

        b1 = new Button("1");
        b1.setBounds(80, 230, 50, 50);
        b1.addActionListener(this);
        f.add(b1);

        b2 = new Button("2");
        b2.setBounds(140, 230, 50, 50);
        b2.addActionListener(this);
        f.add(b2);

        b3 = new Button("3");
        b3.setBounds(200, 230, 50, 50);
        b3.addActionListener(this);
        f.add(b3);

        minus = new Button("-");
        minus.setBounds(260, 230, 50, 50);
        minus.addActionListener(this);
        f.add(minus);

        b0 = new Button("0");
        b0.setBounds(80, 290, 50, 50);
        b0.addActionListener(this);
        f.add(b0);

        point = new Button(".");
        point.setBounds(140, 290, 50, 50);
        point.addActionListener(this);
        f.add(point);

        equal = new Button("=");
        equal.setBounds(200, 290, 50, 50);
        equal.addActionListener(this);
        f.add(equal);

        plus = new Button("+");
        plus.setBounds(260, 290, 50, 50);
        plus.addActionListener(this);
        f.add(plus);
    }
    public void actionPerformed(ActionEvent e){
        if(e.getSource() == b7){
            dis *= 10; dis += 7;
            String display = String.valueOf(dis);
            tf.setText(display);
        }
        else if(e.getSource() == b8){
            dis *= 10; dis += 8;
            String display = String.valueOf(dis);
            tf.setText(display);
        }
        else if(e.getSource() == b9){
            dis *= 10; dis += 9;
            String display = String.valueOf(dis);
            tf.setText(display);
        }
        else if(e.getSource() == b4){
            dis *= 10; dis += 4;
            String display = String.valueOf(dis);
            tf.setText(display);
        }
        else if(e.getSource() == b5){
            dis *= 10; dis += 5;
            String display = String.valueOf(dis);
            tf.setText(display);
        }
        else if(e.getSource() == b6){
            dis *= 10; dis += 6;
            String display = String.valueOf(dis);
            tf.setText(display);
        }
        else if(e.getSource() == b1){
            dis *= 10; dis += 1;
            String display = String.valueOf(dis);
            tf.setText(display);
        }
        else if(e.getSource() == b2){
            dis *= 10; dis += 2;
            String display = String.valueOf(dis);
            tf.setText(display);
        }
        else if(e.getSource() == b3){
            dis *= 10; dis += 3;
            String display = String.valueOf(dis);
            tf.setText(display);
        }
        else if(e.getSource() == b0){
            dis *= 10; dis += 0;
            String display = String.valueOf(dis);
            tf.setText(display);
        }
        else if(e.getSource() == plus){
            if(choice == 1){
                temp += dis;
                dis = 0;
            }
            else if(choice == 2){
                temp -= dis;
                dis = 0;
            }
            else if(choice == 3){
                temp *= dis;
                dis = 0;
            }
            else if(choice == 4){
                temp /= dis;
                dis = 0;
            }
            else{
                choice = 1;
                temp = dis;
                dis = 0;
            }
            String disp = String.valueOf(temp);
            tf.setText(disp);
        }
        else if(e.getSource() == minus){
            if(choice == 1){
                temp += dis;
                dis = 0;
            }
            else if(choice == 2){
                temp -= dis;
                dis = 0;
            }
            else if(choice == 3){
                temp *= dis;
                dis = 0;
            }
            else if(choice == 4){
                temp /= dis;
                dis = 0;
            }
            else{
                choice = 2;
                temp = dis;
                dis = 0;
            }
            String disp = String.valueOf(temp);
            tf.setText(disp);
        }
        else if(e.getSource() == mult){
            if(choice == 1){
                temp += dis;
                dis = 0;
            }
            else if(choice == 2){
                temp -= dis;
                dis = 0;
            }
            else if(choice == 3){
                temp *= dis;
                dis = 0;
            }
            else if(choice == 4){
                temp /= dis;
                dis = 0;
            }
            else{
                choice = 3;
                temp = dis;
                dis = 0;
            }
            String disp = String.valueOf(temp);
            tf.setText(disp);
        }
        else if(e.getSource() == div){
            if(choice == 1){
                temp += dis;
                dis = 0;
            }
            else if(choice == 2){
                temp -= dis;
                dis = 0;
            }
            else if(choice == 3){
                temp *= dis;
                dis = 0;
            }
            else if(choice == 4){
                temp /= dis;
                dis = 0;
            }
            else{
                choice = 4;
                temp = dis;
                dis = 0;
            }
            String disp = String.valueOf(temp);
            tf.setText(disp);
        }
        else if(e.getSource() == equal){
            if(choice == 1){
                temp += dis;
            }
            else if(choice == 2){
                temp -= dis;
            }
            else if(choice == 3){
                temp *= dis;
            }
            else if(choice == 4){
                temp /= dis;
            }
            dis = temp;
            temp = 0;
            choice = 0;
            String display = String.valueOf(dis);
            tf.setText(display);
            dis = 0;
        }
    }
    public static void main(String[] args){
        new Calculator2();
    }
}