Lab 12: Part 1: Non-fruitful Recursion

Create a new file called lab12.py. All the functions you write today will be recursive, and in this section, non-fruitful. Your functions will print, but not return values. Later on today, you'll move on to fruitful recursive functions.

Task 0. divideBy3

Partner A

Write a function called divideBy3 that will take a number and divide the number by 3, printing the number unless it is less than or equal to 1. This function must be recursive.

>>> divideBy3(3)
  3

>>> divideBy3(1)

>>> divideBy3(0)

>>> divideBy3(-4)

>>> divideBy3(15)
  15
  5.0
  1.6666666666666667

>>> divideBy3(100)
  100
  33.333333333333336
  11.111111111111112
  3.703703703703704
  1.234567901234568

Task 1. Recursive triangles

Partner B

In this task, you will create some recursive patterns using asterisks.

Write a Python function called asteriskTriangle that will take a length parameter and draw a triangle pattern composed of lines of asterisks that get successively smaller with each line.

This function must be recursive.

Example invocations of asteriskTriangle: 

>>> asteriskTriangle(1)
  *

>>> asteriskTriangle(3)
  ***
  **
  *

>>> asteriskTriangle(5)
  *****
  ****
  ***
  **
  *

>>> asteriskTriangle(15)
  ***************
  **************
  *************
  ************
  ***********
  **********
  *********
  ********
  *******
  ******
  *****
  ****
  ***
  **
  *

>>> asteriskTriangle(0)

>>>

Task 2. switch

Partner B

Write a function called switch that will take a length parameter and draw a pattern like the examples below. The examples below always use asterisks and dashes:* and -. You can change those if you like, or, even better, add parameters so the user can specify their own symbols. This function must be recursive.

>>> switch(0)

>>> switch(1)

>>> switch (2)
  **

>>> switch(3)
  ***---
  **
  ---***

>>> switch(6)
  ******------
  *****-----
  ****----
  ***---
  **
  ---***
  ----****
  -----*****
  ------******

>>> switch(8)
  ********--------
  *******-------
  ******------
  *****-----
  ****----
  ***---
  **
  ---***
  ----****
  -----*****
  ------******
  -------*******
  --------********

Table of Contents