在主类中找不到符号

Question

Calculator class: (contains the arithmetic methods)

package mycalcgie;

import java.util.*;

class Calculator {

public int TEMP, SolveTEMP;

public static void Add (int TEMP, int SolveTEMP){

    SolveTEMP += TEMP;

}

public static void Subtract (int TEMP, int SolveTEMP){

    SolveTEMP -= TEMP;

}

public static void Divide (int TEMP, int SolveTEMP){

    SolveTEMP /= TEMP;

}

public static void Multiply (int TEMP, int SolveTEMP){

    SolveTEMP *= TEMP;

}


}

WindowedCalculator class: (contains the GUI)

package mycalcgie;

import java.awt.event.*;
import javax.swing.*;
import java.awt.*;

class WindowedCalculator extends Calculator{

 JButton Num1;
 JButton Num2;
 JButton Num3;
 JButton Num4;
 JButton Num5;
 JButton Num6;
 JButton Num7;
 JButton Num8;
 JButton Num9;
 JButton Num0;
 JButton Equal;
 JButton AddBt;
 JButton Subtractbt;
 JButton Multiplybt;
 JButton Dividebt;
 JButton Solvebt;
 JButton Clearbt;
 JTextField Result;
 int TEMP;
 int SolveTEMP;

Boolean addBool = false ;
Boolean subBool = false ;
Boolean divBool = false ;
Boolean mulBool = false ;

String display = "";

public WindowedCalculator() {

    JPanel p1 = new JPanel();
    p1.setLayout(new GridLayout(4, 3));
    p1.add(Num1 = new JButton("1"));
    p1.add(Num2 = new JButton("2"));
    p1.add(Num3 = new JButton("3"));
    p1.add(Num4 = new JButton("4"));
    p1.add(Num5 = new JButton("5"));
    p1.add(Num6 = new JButton("6"));
    p1.add(Num7 = new JButton("7"));
    p1.add(Num8 = new JButton("8"));
    p1.add(Num9 = new JButton("9"));
    p1.add(Num0 = new JButton("0"));
    p1.add(Clearbt = new JButton("C"));

    JPanel p2 = new JPanel();
    p2.setLayout(new FlowLayout());
    p2.add(Result = new JTextField(10));
    Result.setHorizontalAlignment(JTextField.RIGHT);
    Result.setEditable(true);

    JPanel p3 = new JPanel();
    p3.setLayout(new GridLayout(5, 1));
    p3.add(AddBt = new JButton("+"));
    p3.add(Subtractbt = new JButton("-"));
    p3.add(Multiplybt = new JButton("*"));
    p3.add(Dividebt = new JButton("/"));
    p3.add(Solvebt = new JButton("="));

    JPanel p = new JPanel();
    p.setLayout(new GridLayout());
    p.add(p2, BorderLayout.NORTH);
    p.add(p1, BorderLayout.SOUTH);
    p.add(p3, BorderLayout.EAST);


    Num1.addActionListener(new ListenToOne());
    Num2.addActionListener(new ListenToTwo());
    Num3.addActionListener(new ListenToThree());
    Num4.addActionListener(new ListenToFour());
    Num5.addActionListener(new ListenToFive());
    Num6.addActionListener(new ListenToSix());
    Num7.addActionListener(new ListenToSeven());
    Num8.addActionListener(new ListenToEight());
    Num9.addActionListener(new ListenToNine());
    Num0.addActionListener(new ListenToZero());

    AddBt.addActionListener(new ListenToAdd());
    Subtractbt.addActionListener(new ListenToSubtract());
    Multiplybt.addActionListener(new ListenToMultiply());
    Dividebt.addActionListener(new ListenToDivide());
    Solvebt.addActionListener(new ListenToSolve());
    Clearbt.addActionListener(new ListenToClear()); 
}   


class ListenToClear implements ActionListener {
    public void actionPerformed(ActionEvent e) {
    //display = Result.getText();
        Result.setText("");
        addBool = false ;
        subBool = false ;
        mulBool = false ;
        divBool = false ;

        TEMP = 0;
        SolveTEMP = 0;
    }
}
class ListenToOne implements ActionListener {
    public void actionPerformed(ActionEvent e) {
        display = Result.getText();
        Result.setText(display + "1");
    }
}   

class ListenToTwo implements ActionListener {
    public void actionPerformed(ActionEvent e) {
        display = Result.getText();
        Result.setText(display + "2");
    }
}
class ListenToThree implements ActionListener {
    public void actionPerformed(ActionEvent e) {
        display = Result.getText();
        Result.setText(display + "3");
    }
}
class ListenToFour implements ActionListener {
    public void actionPerformed(ActionEvent e) {
        display = Result.getText();
        Result.setText(display + "4");
    }
}
class ListenToFive implements ActionListener {
    public void actionPerformed(ActionEvent e) {
        display = Result.getText();
        Result.setText(display + "5");
    }
}
class ListenToSix implements ActionListener {
    public void actionPerformed(ActionEvent e) {
        display = Result.getText();
        Result.setText(display + "6");
    }
}
class ListenToSeven implements ActionListener {
    public void actionPerformed(ActionEvent e) {
        display = Result.getText();
        Result.setText(display + "7");
    }
}
class ListenToEight implements ActionListener {
    public void actionPerformed(ActionEvent e) {
        display = Result.getText();
        Result.setText(display + "8");
    }
}
class ListenToNine implements ActionListener {
    public void actionPerformed(ActionEvent e) {
        display = Result.getText();
        Result.setText(display + "9");
    }
}
class ListenToZero implements ActionListener {
    public void actionPerformed(ActionEvent e) {
        display = Result.getText();
        Result.setText(display + "0");
    }
}

class ListenToAdd implements ActionListener {
    public void actionPerformed(ActionEvent e) {
        TEMP = Integer.parseInt(Result.getText());
                Result.setText("+");
                addBool = true ;

    }
}
class ListenToSubtract implements ActionListener {
    public void actionPerformed(ActionEvent e) {
        TEMP = Integer.parseInt(Result.getText());
        Result.setText("-");
        subBool =true;
    }
}
class ListenToMultiply implements ActionListener {
    public void actionPerformed(ActionEvent e) {
        TEMP = Integer.parseInt(Result.getText());
        Result.setText("*");
        mulBool =true;

    }
}
class ListenToDivide implements ActionListener {
    public void actionPerformed(ActionEvent e) {
        TEMP = Integer.parseInt(Result.getText());
        Result.setText("/");
        divBool =true;
    }
}

class ListenToSolve implements ActionListener {
    public void actionPerformed(ActionEvent e) {
        SolveTEMP = Integer.parseInt( Result.getText() );

        if ( addBool == true  )
            WindowedCalculator.Add (TEMP, SolveTEMP);

        else if ( subBool == true  )
            WindowedCalculator.Subtract (TEMP, SolveTEMP);

        else if ( mulBool == true  )
            WindowedCalculator.Multiply (TEMP, SolveTEMP);

        else if ( divBool == true  )
            WindowedCalculator.Divide (TEMP, SolveTEMP);

    Result.setText(  Integer.toString( SolveTEMP ) );

    addBool = false ;
    subBool = false ;
    mulBool = false ;
    divBool = false ;

    }
}

/*public static void main(String[] args) {
// TODO Auto-generated method stub
    WindowedCalculator calc = new WindowedCalculator();
    calc.pack();
    calc.setLocationRelativeTo(null);
    calc.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    calc.setVisible(true);
}*/


}       

Tester class: (contains the main method)

package mycalcgie;

import java.awt.event.*;
import javax.swing.*;
import java.awt.*;
import java.util.*;

class Tester extends WindowedCalculator {

public static void main(String[] args) {

    WindowedCalculator calc = new WindowedCalculator();
    calc.pack();
    calc.setLocationRelativeTo(null);
    calc.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    calc.setVisible(true);

}
}

Everything compiles except for Tester.java. It is returning 4 cannot find symbol errors saying variable calc of the type WindowedCalculator .

Answer 1

You cannot access instance fields without an instance of the class.

You probably want to make those fields static.

Answer 2

The methods that you are trying to call on WindowedCalculator are methods of the JFrame class. You should make WindowedCalculator extend JFrame.

After that, you will want WindowedCalculator to call Calculator to perform your various arithmetic operations.

However, it looks like you have errors in your Calculator class. When you pass in int values, they are passed as values. When you do something like SolveTEMP += TEMP , you are only changing the value of SolveTEMP locally, within your method. You should probably change that to: return SolveTEMP + TEMP; , change the method's return type to int , and get rid of the class level variables you have declared (that is, SolveTEMP and TEMP).