Class 26 — Wednesday March 25

Module implementation and usage

Practice makes perfect — Is more than a platitude — Take it to your heart

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Look both ways

• Back or ahead

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Agenda

• Function-based chrestomathics

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Buddying

• A possible form for finding a classmate buddy

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Slides

• PDF

• Show

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Downloads

• Module uva.py

• Implement a worthwhile module with several functions based on your suggestions

• Tester program rotunda.py

• Needs to be augmented based on your ideas for your ideas on uva.py

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• Module primal.py

• Defines three functions relating to factorization and primality.

• None of the functions should get input or print output.

• Tester program factoid.py

• Performs basic testing of module primal.py

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To do

• Review artifacts and prior function materials.

• Watch the recording of today's class.

• Complete Homework 23

• Preview next class activities activities

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Module uva: freestyling

• Implement a worthwhile module with several functions based on your suggestions

• Some suggestions already received

• Function credits_to_go()

• Has one integer parameter n, which is the number of credits earned so far.

• Returns the remaining number of credits needed to graduate.

• Assumption: CLAS student so 120 credits is amount needed.

• Function how_old_is_UVA()

• Has no parameters

• Returns the number of years since UVA was founded.

• Not sure want to do this one — sticky wicket

• Function grade_as_percent( score, total )

• Has two parameters numeric parameters score and total, where score is points earned and total is the maximum number of points possible.

• Returns the percentage grade given score and total. As student-specified, the return should include a % at the end of the percentage. For example, the following code segment

s = 17

t = 20

pct = uva.grade_as_percent( s, t )

print( "grade_as_percent(", s, ",", t, "):", pct )

should print

grade_as_percent( 17, 20 ): 85.0%

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Module primal: to be submitted to document your participation

• Concerned with integer factorization and primality

• y is a factor of x, if the remainder of x / y is 0.

• x is prime, if its only factors are 1 and itself.

• x and y are relatively prime, if y is not a factor of x and x is not a factor of y

• Function is_factor( x, y )

• Parameters x and y are integers. The function returns whether y is a factor of x.

• Observation

• The % is the Python remainder operator.

• Possible algorithm

• Determine remainder of x divided by y

• By looking at the remainder we can tell whether to return True or False

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• Function is_prime( x )

• Parameter x is an integer. The function returns whether x is prime.

• Questions

• Could is_factor() help?

• What are the possible range of values do we need check for being possible factors of x.

• Does the function need a loop?

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• Function are_relative_primes( x, y )

• Parameters x and y are integers. The function returns whether x and y are relatively prime.

• Questions

• Could is_prime() help?

• Could is_factor() help?

• Do we need both of them?

• Does the function need a loop?

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Slide show

 

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© 2020 Jim Cohoon

Resources from previous semesters are available.