/**
 * Purpose: A class from which objects might be created, which behave like
 *          complex numbers.  Private variables are used to demonstrate
 *          good programming practice.
 */

public class Complex
{
    // private class variables
    private double realpart;
    private double imagpart;

    // default constructor, real and imaginary parts are initialised to zero.
    public Complex()
    {
        realpart = 0;
        imagpart = 0;
        return;
    }

    // another constructor
    public Complex(double x, double y)
    {
        realpart = x;
        imagpart = y;
        return;
    }

    // method to find out value of real part
    public double getReal()
    {
        return realpart;
    }

    // method to find out value of imaginary part
    public double getImag()
    {
        return imagpart;
    }

    // method to add complex "z" onto this object
    public void increaseBy(Complex z)
    {
        realpart += z.getReal();
        imagpart += z.getImag();
        return;
    }

    // method to add together two complex numbers and return the result
    public static Complex add(Complex z, Complex w)
    {
	Complex sum = new Complex();
	sum.realpart = z.getReal() + w.getReal();
	sum.imagpart = z.getImag() + w.getImag();
	return sum;
    }

    // method to print out in usual complex number form
    public void print()
    {
        System.out.print(realpart);
	if (imagpart < 0)
	{
	    System.out.print(" - " + (-1*imagpart) + "i");
	}
	else if (imagpart > 0)
	{
	    System.out.print(" + " + imagpart + "i");
	}
	System.out.println("");
        return;
    }

}