Complex Numbers

package chapter09;

import javax.swing.JOptionPane;

public class ComplexNumberGuiDriver {

    // test client
    public static void main(String[] args) {
        final String TITLE = "ComplexNumber Demo";
        JOptionPane.showMessageDialog(null, "Running " + TITLE + "\nHave Fun!!!", TITLE,
                JOptionPane.INFORMATION_MESSAGE);

        do {
            // generate two Complex Number a and b, and test them;
            JOptionPane.showMessageDialog(null, "Generate Complex Number 1: ", TITLE, JOptionPane.INFORMATION_MESSAGE);
            Complex a = generateComplexNumber();
            test(a);

            JOptionPane.showMessageDialog(null, "Generate Complex Number 2: ", TITLE, JOptionPane.INFORMATION_MESSAGE);
            Complex b = generateComplexNumber();
            test(b);

            // operate Complex Number a and b;
            Complex ans = null;
            String options[] = { "Add", "Subtract", "Multiply", "Divide", "Distance", "Compare", "Quit" };
            int option = JOptionPane.showOptionDialog(null, "Choose Operation", TITLE, JOptionPane.YES_NO_CANCEL_OPTION,
                    JOptionPane.PLAIN_MESSAGE, null, options, 4);
            String output = "";
            switch (option) {
            case 0:
                ans = a.add(b);
                output = " + ";
                break;
            case 1:
                ans = a.subtract(b);
                output = " - ";
                break;
            case 2:
                ans = a.multiply(b);
                output = " * ";
                break;
            case 3:
                ans = a.divide(b);
                output = " / ";
                break;
            default:
                break;
            }
            if (option == 4) {
                JOptionPane.showMessageDialog(null, a + " and " + b + " 's diatance = " + a.distance(b), TITLE,
                        JOptionPane.PLAIN_MESSAGE);
            } else if (option == 5) {
                if (a.equals(b))
                    JOptionPane.showMessageDialog(null, a + " is equals to " + b, TITLE, JOptionPane.PLAIN_MESSAGE);
                else if (a.greaterThan(b))
                    JOptionPane.showMessageDialog(null, a + " is greater than " + b, TITLE, JOptionPane.PLAIN_MESSAGE);
                else
                    JOptionPane.showMessageDialog(null, a + " is less than " + b, TITLE, JOptionPane.PLAIN_MESSAGE);

            } else if (option > 4)
                break;
            else {
                String sen = "(" + a + ")" + output + "(" + b + ") " + " = " + ans;
                JOptionPane.showMessageDialog(null, sen, TITLE, JOptionPane.PLAIN_MESSAGE);
            }

            // do this again?
            option = JOptionPane.showConfirmDialog(null, "Do you want to do this again?", TITLE,
                    JOptionPane.YES_NO_OPTION, JOptionPane.QUESTION_MESSAGE);
            if (option != JOptionPane.YES_OPTION)
                break;
        } while (true);
    }

    // generate Complex Number
    public static Complex generateComplexNumber() {
        double real, imag;
        final String TITLE = "ComplexNumber Demo";
        String temp;
        temp = JOptionPane.showInputDialog(null, "Enter Real of Complex Number", TITLE,
                JOptionPane.INFORMATION_MESSAGE);
        if (temp == null)
            return null;
        real = Double.parseDouble(temp);

        temp = JOptionPane.showInputDialog(null, "Enter Imaginary Components of Complex Number", TITLE,
                JOptionPane.INFORMATION_MESSAGE);
        if (temp == null)
            return null;
        imag = Double.parseDouble(temp);
        Complex a = new Complex(real, imag);
        return a;
    }

    // test the methods: abs(), negate(), conjugate()
    public static void test(Complex a) {
        final String TITLE = "Test Complex Number";

        do {
            Complex ans1 = null;
            String options1[] = { "Negate", "Conjugate", "Abs", "Quit" };
            int option = JOptionPane.showOptionDialog(null, a.toString(), TITLE, JOptionPane.YES_NO_CANCEL_OPTION,
                    JOptionPane.PLAIN_MESSAGE, null, options1, 3);
            switch (option) {
            case 0:
                ans1 = a.negate();
                JOptionPane.showMessageDialog(null, a + "'s negation is " + ans1, TITLE, JOptionPane.PLAIN_MESSAGE);
                break;
            case 1:
                ans1 = a.conjugate();
                JOptionPane.showMessageDialog(null, a + "'s conjugate is " + ans1, TITLE, JOptionPane.PLAIN_MESSAGE);
                break;
            case 2:
                double dis = a.abs();
                JOptionPane.showMessageDialog(null, a + "'s distance is " + dis, TITLE, JOptionPane.PLAIN_MESSAGE);
                break;
            default:
                break;
            }
            if (option > 3)
                break;
            option = JOptionPane.showConfirmDialog(null, "Do you want test again?", TITLE, JOptionPane.YES_NO_OPTION,
                    JOptionPane.QUESTION_MESSAGE);
            if (option != JOptionPane.YES_OPTION)
                break;
        } while (true);
    }
}

class Complex {

    // define two doubles, known as the real part and the imaginary part.
    private double real;
    private double imag;

    // define 4 constructors
    public Complex(double real, double imag) {
        this.real = real;
        this.imag = imag;
    }

    public Complex(double real) {
        this.real = real;
        this.imag = 0;
    }

    public Complex() {
        this(0, 0);
    }

    // the constructor takes a String
    public Complex(String str) {
        String newStr = str.trim();
        char[] chars = newStr.toCharArray();
        if (newStr.indexOf("i") == -1)
            this.real = Double.parseDouble(newStr);
        else if (chars.length == 1) {
            this.imag = 1.0;
        } else if (chars.length == 2) {
            this.imag = (double) (chars[0] - '0');
        } else if (chars.length == 3) {
            if (Character.isDigit(chars[0])) {
                this.real = (double) (chars[0] - '0');
                this.imag = (chars[1] == '-') ? -1.0 : 1.0;
            } else
                this.imag = -(double) (chars[1] - '0');
        } else if (chars.length == 4) {
            if (Character.isDigit(chars[0])) {
                this.real = (double) (chars[0] - '0');
                this.imag = (chars[1] == '-') ? -(double) (chars[2] - '0') : (double) (chars[2] - '0');
            } else {
                this.real = -(double) (chars[1] - '0');
                this.imag = (chars[2] == '-') ? -1.0 : 1.0;
            }
        } else if (chars.length == 5) {
            this.real = -(double) (chars[1] - '0');
            this.imag = (chars[2] == '-') ? -(double) (chars[3] - '0') : (double)(chars[3] - '0');
        }
    }

    // define public methods
    public double getReal() {
        return real;
    }

    public double getImag() {
        return imag;
    }

    public Complex add(Complex c) {
        return new Complex((this.real + c.getReal()), (this.imag + c.getImag()));
    }

    public Complex subtract(Complex c) {
        return new Complex((this.real - c.getReal()), (this.imag - c.getImag()));
    }

    public Complex multiply(Complex c) {
        return new Complex((this.real * c.getReal() - this.imag * c.getImag()),
                (this.real * c.getImag() + c.getImag() * c.getImag()));
    }

    public Complex divide(Complex c) {
        double a = this.real;
        double b = this.imag;
        double x = c.getReal();
        double y = c.getImag();
        return new Complex((a * x + b * y) / (x * x + y * y), (b * x - a * y) / (x * x + y * y));
    }

    public double abs() {
        double a = this.getReal();
        double b = this.getImag();
        return Math.sqrt(a * a + b * b);
    }

    public Complex negate() {
        double a = this.getReal();
        double b = this.getImag();
        return new Complex(-a, -b);
    }

    public Complex conjugate() {
        return new Complex(this.getReal(), -this.getImag());
    }

    public double distance(Complex c) {
        double x = this.getReal() - c.getReal();
        double y = this.getImag() - c.getImag();
        return x * x + y * y;
    }

    public boolean equals(Complex c) {
        double minus = (this.abs() > c.abs()) ? (this.abs() - c.abs()) : -(this.abs() - c.abs());
        if (minus / this.abs() < 1E-6)
            return true;
        return false;
    }

    public boolean greaterThan(Complex c) {
        return (this.abs() > c.abs()) ? true : false;
    }

    public boolean lessThan(Complex c) {
        return !this.greaterThan(c);
    }

    public String toString() {
        if (this.getImag() > 0)
            return this.getReal() + "+" + (this.getImag() + "i");
        else if (this.getImag() == 0)
            return this.getReal() + "";
        else
            return this.getReal() + "" + (this.getImag() + "i");
    }

}