## Homework 4 - Lissajous Curves

A Lissajous curve
is the graph of the system of parametric equations given by

x = A * sin(a * θ + d)
y = B * sin(b * θ)

In this lab, you will write a program that will draw Lissajous curves
where A = B = 1 and a, b, and d are entered by the user.

### Output Requirements

Write a graphics program that draws a Lissajous curve in a graphics window.

### Input Requirements

The user enters the values of a, b, and d in that order. The program will
terminate when the user enters a non-positive value for a. The value of d will be entered in
degrees (and converted to radians by your application).

### Process Requirements

After the user has entered the desired parameters, your application will
clear the graphics window and draw the corresponding Lissajous curve.

### Miscellaneous Requirements

The graphics window should be 401 pixels wide and 401 pixels high. The title
of the graphics window should be "Lissajous Curve".

Since A and B are both one, the values of x and y will range from -1 to
1. Your world coordinate system should go from -1.1 to 1.1 in order to allow
a bit of a margin around the Lissajous curve.

The actual drawing of the Lissajous curve should be done using a function named "drawLissajous".
Here is the prototype of this function:

//---------------------------------------------------------
// drawLissajous
//
// Draw a curve in the specified world coordinate system
// based on the parametric equations
//
// x = sin(a*theta + d)
// y = sin(b*theta)
//
// where theta runs from 0 to 2*PI.
//
// In parameters: w, a, b, d
//---------------------------------------------------------
void drawLissajous(worldType w, double a, double b, double d)

### Sample Run

A sample run showing both the console window and the resulting graphics
window is illustrated below:

### File Submission

Email me your Lab04 project file (PRJ) and program file (cpp) as email
attachments.