As usual, create two directories for today's class. Create a
directory called lecture9 under activities, and
a directory called lab9 under labs.
Up to now, in order to get repeated behavior we had to copy and paste code or call functions multiple times. That, however, is not the most efficient mechanism for getting repeated behavior. Today, we will learn about for loops.
In a file called polygon.py, create a function called
draw_polygon that takes as parameters the x and y coordinates
of the polygon, as well as the number of sides in the polygon. This
function should use the turtle module to draw a polygon at the coordinates
specified by the user with the specified number of sides.
Your turtle drawings have been limited to black lines on a white
background. However, it is fairly easy to change the color that
turtle draws in. Using the turtle.color function, we can
start creating more appealing looking drawings.
Create a function called draw_parabola in a file
called parabola.py. The function should draw the
function:
y=x2/100
with the domain:
−(w/2)<x<(w/2)
and the range:
−(h/2)<y<(h/2)
where w
and h are the width and height of
the window. The
functions window_height
and window_width
in the turtle module can be used to get the dimensions of
the window.
You should draw the major axis in one color, and the plot of the function in another color. Play with the step to find a decent representation of the function.
If you structure your code well enough, you should be able to easily alter the function being plotted. Find a more interesting function, and attempt to plot it using your function. You will not get full points for the lab if your code plots the above function.
When you have finished, create a tar file of your lab9
directory. To create a tar file, execute the following commands:
cd ~/cs120/labs tar czf lab9.tgz lab9/
To submit your activity, go to cseval.roanoke.edu. You should
see an available assignment called Lab Assignment 9. Only
one of your pair should submit your activity. Make sure both partners
are listed in the header of your file.
Do not forget to email your partner todays files!