ComplexNumbers

public class Complex {

    private final double real;
    private final double imaginary;

    /** A convenience method, shorter than a constructor call, for
     * creating complex numbers.
     * @param real The real component of the number.
     * @param imaginary The imaginary component of the number.
     * @return An immutable instance of <code>Complex</code>
     * representing the indicated number.
     */
    public Complex(double real, double imaginary) {
        this.real = real;
        this.imaginary = imaginary;
    }

    /** The real component of this number. */
    public double getReal() {
        return this.real;
    }

    /** The imaginary component of this number. */
    public double getImaginary(){
        return this.imaginary;
    }

    public boolean isZero(){
        return this.real == 0 && this.imaginary == 0;
    }

    public double getMagnitude(){
        return Math.hypot(real, imaginary);
    }

    public Complex add(Complex that){
        Complex a = this;
        double real = a.real + that.real; // or a.getReal() + that.getReal();
        double imaginary = a.getImaginary() + that.getImaginary();
        return new Complex(real, imaginary);
    }

    public Complex subtract(Complex that){
        Complex a = this;
        double real = a.real - that.real;
        double imaginary = a.getImaginary() - that.getImaginary();
        return new Complex(real, imaginary);
    }

    /** Returns the product of this number and <code>that</code>.  Does
     * not change either <code>this</code> or the argument.  We use the
     * standard definition of complex arithmetic; see for example
     * http://mathworld.wolfram.com/ComplexNumber.html .  */
    public Complex multiply(Complex that){
        Complex a = this;
        double real = (a.real * that.real) - (a.imaginary * that.imaginary);
        double imaginary =
                (a.getReal() * that.getImaginary()) + (a.getImaginary() * that.getReal());
        return new Complex(real, imaginary);
    }

    /** Returns the quotient of this number over <code>that</code>.
     * Does not change either <code>this</code> or the argument.  We use
     * the standard definition of complex arithmetic; see for example
     * http://mathworld.wolfram.com/ComplexNumber.html .  */
    public Complex dividedBy(Complex that){
        // FILL IN
        // Multiply the expression by the conjugate of the divisor/denominator!!!!

        return this;

    }

    public Complex conjugate() {
        return new Complex(real, -imaginary); // CALL THIS METHOD IN THE dividedBy() method!
    }
    public Complex reciprocal() {
        return this; // FILL IN THEN CALL THIS METHOD IN THE dividedBy() method!

    }
}