This notebook was prepared by Donne Martin. Source and license info is on GitHub.

Challenge Notebook

Problem: Given a real number between 0 and 1, print the binary representation. If the length of the representation is > 32, return 'ERROR'.


  • Is the input a float?
    • Yes
  • Is the output a string?
    • Yes
  • Is 0 and 1 inclusive?
    • No
  • Does the result include a trailing zero and decimal point?
    • Yes
  • Is the leading zero and decimal point counted in the 32 char limit?
    • Yes
  • Can we assume the inputs are valid?
    • No
  • Can we assume this fits memory?
    • Yes

Test Cases

  • None -> 'ERROR'
  • Out of bounds (0, 1) -> 'ERROR'
  • General case
    • 0.625 -> 0.101
    • 0.987654321 -> 'ERROR'


Refer to the Solution Notebook. If you are stuck and need a hint, the solution notebook's algorithm discussion might be a good place to start.


In [ ]:
class Bits(object):

    def print_binary(self, num):
        # TODO: Implement me

Unit Test

The following unit test is expected to fail until you solve the challenge.

In [ ]:
# %load
import unittest

class TestBits(unittest.TestCase):

    def test_print_binary(self):
        bit = Bits()
        self.assertEqual(bit.print_binary(None), 'ERROR')
        self.assertEqual(bit.print_binary(0), 'ERROR')
        self.assertEqual(bit.print_binary(1), 'ERROR')
        num = 0.625
        expected = '0.101'
        self.assertEqual(bit.print_binary(num), expected)
        num = 0.987654321
        self.assertEqual(bit.print_binary(num), 'ERROR')
        print('Success: test_print_binary')

def main():
    test = TestBits()

if __name__ == '__main__':

Solution Notebook

Review the Solution Notebook for a discussion on algorithms and code solutions.