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CS111 Lab #9: Recursion and Iteration
You do not need to turn in this lab.
1. Turtles drawing polygons
Last week in lecture you were introduced to turtles, which could draw
patterns to the applet window. In this lab you will program turtles to
draw regular polygons. A regular polygon has sides of equal length and
angles of equal length, as shown in the following images:
We will draw these polygons using:
- Tail Recursion.
- While loop.
- For loop.
To accomplish this, first download the Turtles folder from the CS111
download folder. Open the Project window. Drag PolygonWorld.java and PolygonWorld.html into the project window.
We will start by filling in the method: drawSides to draw a polygon
using recursion. The polygon is defined by the number of sides and the
length of a side. A turtle can draw a polygon by repeatedly drawing a
side and then turning by an angle of (360.0/numSides), until it has drawn
the correct number of sides.
Now we will write polygonWhile, and polygonFor--Two methods that will
draw polygons using while and for loops, respectively.
2. Polygon Flowers
Now that you can draw a polygon, you can use this method to draw polygon
flower. A polygon flower is defined by the number of petals and the
number of sides of each petal. Each petal is a regular polygon, and the
petals are rotated with respect to one another. The angle of rotation
is equal to (360.0/numPetals). Some sample flowers are as follows:
As with the polygon, we will write methods to draw these flowers
using tail recursion, while loops and for loops.
You do not need to turn in this lab.
