sierpinski.py

Below is the syntax highlighted version of sierpinski.py from §2.2 Modules and Clients.

#-----------------------------------------------------------------------
# sierpinski.py
#-----------------------------------------------------------------------

import sys
import stddraw
import stdrandom

# Accept integer n as a command-line argument. Play chaos game on
# triangle to produce Sierpinski triangle of n points.

def main():
    n = int(sys.argv[1])

    cx = [0.000, 1.000, 0.500]
    cy = [0.000, 0.000, 0.866]

    x = 0.0
    y = 0.0

    stddraw.setPenRadius(0.0)
    for i in range(n):
        r = stdrandom.uniformInt(0, 3)
        x = (x + cx[r]) / 2.0
        y = (y + cy[r]) / 2.0
        stddraw.point(x, y)
    stddraw.show()

if __name__ == '__main__':
    main()

#-----------------------------------------------------------------------

# python sierpinski.py 1000

# python sierpinski.py 10000

# python sierpinski.py 100000