Need help with drawLine method

Question

Hello,
I've been having trouble with a recent programming assignment and the prof isn't being very helpful. I need to call the drawLine method to plot a line between (0,0) and two coordinates entered by the user; is there a way to do this without a JPanel? Here are the specs:
I've already done Part 1., just posting it to give a complete representation of the assignment.
Part 1. Implement a ComplexNumber class to represent complex numbers (z = a + bi).
1) Instance variables:
private int real; /* real part */
private int imag; /* imaginary part */
2) Constructor:
public ComplexNumber ( int realVal, int imagVal )
{ /* initialize real to realVal and imag to imagVal */ }
3) Get/Set functions:
public int getReal ( )
{ /* returns the real part */ }
public int getImag ( )
{ /* returns the imaginary part */ }
public void setReal ( int realVal )
{ /* sets real to realVal */ }
public void setImag ( int imagVal )
{ /* sets imag to imagVal */ }
Part 2. Implement a ComplexNumberPlot class (with a main method) that gets complex
numbers from the user and plots them. The user will be prompted a complex number until
he/she enters 0. The numbers will be input from the keyboard (System.in) and displayed
in the plot as they are entered. Assume that the user will enter the numbers in blank
separated format. For example, if the user wants to enter three complex numbers: 3 + 4i,
5 + 12i, and 15 + 17i, the input sequence will be:
3 4
5 12
15 17
0 0
To plot a complex number, you need to draw a line between (0,0) and (real, imag) using
the drawLine method.
Name your classes as ComplexNumber and ComplexNumberPlot.
For simplicity, you can assume that the complex numbers input by the user fall
into the first quadrant of the complex plane, i.e. both real and imaginary values
are positive.
Thanks for any help!

Answer 1

Ok I've made some progress, here is what I've got.
public class ComplexNumber
private int real;
private int imag;
public ComplexNumber (int realVal, int imagVal)
real = realVal;
imag = imagVal;
public int getReal()
return real;
public int getImag()
return imag;
public void setReal(int realVal)
real = realVal;
public void setImag(int imagVal)
imag = imagVal;
import java.util.Scanner;
import java.awt.*;
import javax.swing.*;
public class ComplexNumberPlot
public static void main (String [] args)
ComplexNumber num = new ComplexNumber (1,0);
Scanner scan = new Scanner (System.in);
System.out.println("Enter a complex number(s):");
num.setReal(scan.nextInt());
num.setImag(scan.nextInt());
while (num.getReal() + num.getImag() != 0)
num.setReal(scan.nextInt());
num.setImag(scan.nextInt());
System.out.println();
JFrame frame = new JFrame ("ComplexNumberPlot");
frame.setDefaultCloseOperation (JFrame.EXIT_ON_CLOSE);
ComplexPanel panel = new ComplexPanel();
frame.getContentPane().add(panel);
frame.pack();
frame.setVisible(true);
class ComplexPanel extends JPanel
public ComplexPanel()
setPreferredSize (new Dimension(150,150));
public void PaintComponent (Graphics page)
super.paintComponent(page);
page.drawLine(0,0,100,100);
However
1) The JPanel pops up but no line is drawn.
2) I am not sure how to get the variables I'm scanning for to work in the drawLine method
Thanks for all your help so far.