Lecture Notes on 06 Feb 2017

Active Reading: Type code as you read.

Read Chapter 5: Sections 5.1 - 5.2

Write the code from the following listings and run them:

* Listing 5.1: RepeatSubtractionQuiz.py

* Listing 5.2: GuessNumberOneTime.py

* Listing 5.3: GuessNumber.py

* Listing 5.4: SubtractionQuizLoop.py

* Listing 5.5: SentinelValue.py

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

  # count upto num and sum the numbers
  iter = 1
  sum_num = 0
  while (iter <= num):
    sum_num = sum_num + iter
    iter += 1
  print (sum_num)

  # count down to zero from num
  iter = num
  while (iter >= 0):
    print (iter)
    iter = iter - 1

  # sum numbers that are multiples of 3 or 5
  iter = 1
  sum_num = 0
  while (iter < 1000):
    if (iter % 3 == 0) or (iter % 5 == 0):
      sum_num = sum_num + iter
    iter = iter + 1
  print (sum_num)

  # sum of all two digit numbers that are multiples of 15
  iter = 15
  sum_num = 0
  while (iter < 100):
    sum_num = sum_num + iter
    iter = iter + 15

  # use of sentinel value to terminate a loop
  sum_num = 0
  iter = 0
  num = input ("Enter a number, type Q to quit: ")
  while (num != "Q"):
    iter = iter + 1
    num = int (num)
    sum_num += num
    num = input ("Enter a number, type Q to quit: ")
  if (iter > 0):
    avg = sum_num / iter
    print (iter, sum_num, avg)

  # sum the digits of a number
  # prompt the user to enter a positive number
  num = int (input ("Enter a positive number: "))

  sum_digits = 0
  while (num > 0):
    sum_digits += num % 10
    num = num // 10
  print (sum_digits)
   
main()