Lecture Notes on 10 Feb 2017

Active Reading: Type code as you read.

Read Chapter 5: Sections 5.7 - 5.8

Write the code from the following listings and run them:

* Listing 5.11: TestBreak.py

* Listing 5.12: TestContinue.py

* Listing 5.13: PrimeNumber.py


def main():
  # prompt the user to enter a positive integer
  num = int (input ("Enter a positive integer: "))

  # prompt user repeatedly if negative number is entered
  while (num <= 0):
    num = int (input ("Enter a positive integer: "))

  # treat 1 as a special case
  if (num == 1):
    print (num, "is not prime")
    return 

  # define the limit for iteration
  limit = int (num ** 0.5) + 1

  # try all divisors within the limit
  divisor = 2
  is_prime = True
  while (divisor < limit):
    if (num % divisor == 0):
      is_prime = False
      break
    divisor += 1

  # print the result
  if (is_prime):
    print (num, "is prime")
  else:
    print (num, "is not prime")

main()

Challenge Problem:
There is a trucking companing that has a fleet of trucks that operate
between Austin and Dallas. The company has a truck leave Austin on the
hour every hour for Dallas. There is also a truck that leaves Dallas
on the hour every hour for Austin. The journey between Austin and Dallas
takes 4 hours. How many trucks of the parent company does an operator
see on his drive on I-35 from Austin to Dallas?