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Nov 14: Recursive Functions

Learning Objectives

After today's class, you should be able to:

  • Identify the base case and recursive step of the factorial function.
  • Trace a recursive function by hand to predict the number of calls.
  • Write short recursive functions based on mathematical sequences.

Reminders

Submission Points Due
Part A. Unit Testing 15 points Wed 11/19
Part B. Nested Data 50 points Fri 11/21
Part C. Recursion 15 points Tue 12/02
Part D. API Usage 20 points Tue 12/02

POGIL Activity

  • Recursive Functions
    • If you are absent today, complete this activity at home
    • Bring your completed activity to class or office hours

Model 1

factorial.py
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def factorial(n):
    # base case
    if n == 0:
        return 1
    # general case
    product = 1
    for i in range(n, 0, -1):
        product *= i
    return product

Model 2

fibonacci.py
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def fibonacci(n):
    # base case
    if n == 1 or n == 2:
        return 1
    # general case
    return fibonacci(n - 1) + fibonacci(n - 2)

if __name__ == "__main__":
    for i in range(1, 6):
        print(fibonacci(i))