Skip to main content

CS1 Python Subgoals

Section 5.7 While Loops Sentinel

Subgoals for Evaluating a Loop.

  1. Determine Loop Components
    1. Start condition and values
    2. Iteration variable and/or update condition
    3. Termination/final condition
    4. Body that is repeated based on indentation
  2. Trace the loop, writing updated values for every iteration or until you identify the pattern

Subsection 5.7.1

Problem: Given the following code, what is the output if the user enters the values: 10, 15, 20, 25, 30, 35, -1?
print("Enter a negative score to signal the end of input.")
good_scores = 0
score = int(input("Score: "))
while score >= 0:
    if score >= 20:
        good_scores += 1
    score = int(input("Score: "))
print("Number of good scores: ", good_scores)

Subsection 5.7.2 Determine loop components

Starting values:
good_scores = 0
# score will be the integer 10 since that is the first value the user entered
Termination condition: When score is greater than or equal to 0
Body that is repeated based on indentation:
if score >= 20:
    good_scores += 1
score = int(input("Score: "))

Subsection 5.7.3 Trace the loop, writing updated values for every iteration or until you identify the pattern

For every iteration of loop, write down values.
Number of good scores: 4
You have attempted of activities on this page.
PrevTopNext