Fractals with turtle graphics: a CS2 programming exercise for introducing recursion

ABSTRACT

This paper describes a programming exercise developed and used in CS2 classes to help introduce recursive programming. Providing a set of primitives which comprise a graphics system allows the students to focus on top down design and the nature of recursion, rather than on implementation details. The exercise entails drawing approximations of fractals by using the graphics primitives which are provided. The exercise was positively received by the students and provided a basis on which to discuss top down design and the desirability of hiding implementation details.

REFERENCES

• 1: Barcellos, Anthony, "The Fractal Geometry of Mandelbrot," Vol. 15, No. 2, March 1984, 98 - 115.
• 2: Dr. LOGOTM User's Reference Guide, NEC Information Systems, Inc., 1985. (Dr. LOGO is a trademark of Digital Research, Inc.)
• 3: Mandelbrot, Benoit B., The Fractal Geometry of Nature, W. H. Freeman and Company, 1983.

INDEX TERMS

Primary Classification:
  K. Computing Milieux
  K.3 COMPUTERS AND EDUCATION
      K.3.2 Computer and Information Science Education
          Subjects: Curriculum

Additional Classification:
  F. Theory of Computation
  F.4 MATHEMATICAL LOGIC AND FORMAL LANGUAGES
      F.4.1 Mathematical Logic
          Subjects: Recursive function theory

General Terms:
Human Factors, Theory