java Math.sqrt( number and a function

Question

I'm fairly new to Java, I'm making a calculator and I cant seem to get Math.sqrt to work on any number that isn't just a number (i.e. Math.sqrt(6 + 3)). Please could someone tell me what I'm doing wrong.

The equals button:

    //Equals button
    JButton equals = new JButton();
    equals.setText("=");
    panel.add(equals);
    frame.add(panel);

    equals.addActionListener(new ActionListener(){
    public void actionPerformed(ActionEvent eq) {

        if(calculation.getText().contains("Math.sqrt")){
            calculation.setText(calculation.getText().replace("Math.sqrt(", ""));
            calculation.setText(Double.toString(Math.sqrt(Double.valueOf(calculation.getText()).longValue())));
        }
        else{
        double answer = (Equals.eval(calculation.getText()));
        Double answer1 = Double.valueOf(answer);
        calculation.setText(Double.toString(answer));
        }
    }
    });;

The Square root button:

    //root
    JButton root = new JButton();
    root.setText("Sqrt");
    panel.add(root);
    frame.add(panel);
    root.addActionListener(new ActionListener(){
        public void actionPerformed(ActionEvent arg0)   {
            calculation.setText(calculation.getText() + "Math.sqrt(");

        }
    });;

Thanks.

What exactly do you mean when you say you can't get it working? Do you see an error? Strange behavior? Something else? — Kevin Workman, May 04 '15 at 13:17
`Double.valueOf("6 + 3")` won't calculate the sum for you. You need to break the string apart and perform the calculation yourself. — Brett Walker, May 04 '15 at 13:18
... which I don't recommend as an excercise for (Java) beginners. — JimmyB, May 04 '15 at 13:19
You are also replacing `Math.sqrt(` to an empty string to get rid of it, but what about the tail/end parenthesis `)` ? — Matias Cicero, May 04 '15 at 13:20
I have a similar issue, `math.sqrt()` works only correctly when you hand over a number, like `math.sqrt(9)`, so `math.sqrt(5+4)` won't work. — Pascal, May 11 '15 at 09:50

java Math.sqrt( number and a function

0 Answers0