Description

Please read the instructions below carefully and follow them closely.  All problems (and parts of problems) are required except as noted in the instructions below.

 

Important: your filenames must be identical to the filenames given below.  For any functions you are asked to write, the function signature (header) must be exactly as described in the instructions.  That is, you must use the exact function names given in the instructions, you must have the parameters the instructions ask for, and the parameters must be in the order the instructions give.

 

Also important: make sure you always save a backup of your work somewhere safe (such as your D2L locker, dropbox.com, or UA Box).

 

Part I: Function Writing Drills (80 points)

 

In this section you will write a number of functions that do not need turtle graphics.  You can test the correctness of your code by placing test_functions.py in the same folder as your functions.py module (see below) and running the test code.

 

Create a new file called functions.py.  If you’re using the template, get rid of the input(‘Enter to end:’) line.  In the file write the following 8 functions (10 points each):

 

1.) Write a function called print_word that has two parameters.  The first is for an integer (assume it will always be non-negative). The second is for a string.  The function will print the string on the given number of lines, each time preceded by a line number and an arrow.  See the examples below for the format of the output (i.e. if you call your function with the same arguments as in the examples your output should look like the output in the examples).

 

Here are some examples of calling the function with different arguments.  (The code executed is in blue, the output produced is in green):

 

print_word(3, ‘banana’)

• –> banana
• –> banana
• –> banana

 

print_word(4, ‘mississippi’)

• –> mississippi
• –> mississippi
• –> mississippi 4 –> mississippi

 

2.)  Write a function called bacteria that will print out the number of bacteria in a Petri dish as time goes by. The function has two parameters.  The first is an integer giving the number of minutes it takes for a bacterium to split into two new bacteria.  The second is an integer giving the number of bacterial generations to include in the output.  Assume you always begin with a single bacterium in the dish and every bacterium always splits into exactly two bacteria at the end of each time period.

 

Here are some examples of calling the function with different arguments.  (The code executed is in blue, the output produced is in green):

 

bacteria(10, 5)

after 10 minutes:  2 bacteria after 20 minutes:  4 bacteria after 30 minutes:  8 bacteria after 40 minutes:  16 bacteria after 50 minutes:  32 bacteria

 

bacteria(21, 3)

after 21 minutes:  2 bacteria after 42 minutes:  4 bacteria after 63 minutes:  8 bacteria

 

3.) Write a function called convert_to_copper that has three integer parameters.

The first represents a number of gold coins.  The second represents a number of silver coins.  The third represents a number of copper coins.  The function will print the numbers of each type of coin followed by the total value of all of the coins when converted to copper.  The exchange rate for coins is:

 

5 copper pieces (cp) = 1 silver piece (sp)

10 silver pieces = 1 gold piece (gp)

 

Here are some examples of calling the function with different arguments.  (The code executed is in blue, the output produced is in green):

 

convert_to_copper(5, 10, 7) convert_to_copper(15, 23, 12)

5 gp, 10 sp, 7 cp converted to copper is: 307 cp

 

15 gp, 23 sp, 12 cp converted to copper is: 877 cp

 

4.) Write a function called convert_from_copper that takes a single integer argument representing a number of copper pieces.  The function prints out the number of gold pieces (gp), silver pieces (sp), and copper pieces (cp) you would end up with if you first converted as many of the initial copper pieces to gold as possible and then converted as many of the remaining copper pieces as possible to silver pieces.

 

Here are some examples of calling the function with different arguments.  (The code executed is in blue, the output produced is in green):

 

convert_from_copper(200) convert_from_copper(1107) convert_from_copper(3242)

200 copper pieces is: 4 gp, 0 sp, 0 cp

 

1107 copper pieces is: 22 gp, 1 sp, 2 cp

 

3242 copper pieces is: 64 gp, 8 sp, 2 cp

 

5.)  This function requires a bit of preparation first:

 

Try entering each of the following in a Python shell:

 

print(‘Hobbit’ * 10) print(‘Hobbit’ * 2) print(‘Hobbit’ * 1) print(‘Hobbit’ * 0)

Using what you just learned, write a function called repeat_word that has three parameters.

The first is for a word (a string).  The second is for an integer representing a number of rows.  The third is for an integer representing a number of columns.  The function prints the word in a number of rows equal to the value of the rows parameter and each row contains the word repeated a number of times equal to the columns parameter.

 

Here are some examples of calling the function with different arguments.  (The code executed is in blue, the output produced is in green):

 

repeat_word(‘Goblin’, 3, 5)  GoblinGoblinGoblinGoblinGoblin 

GoblinGoblinGoblinGoblinGoblin 

GoblinGoblinGoblinGoblinGoblin

 

     repeat_word(‘Kobold’, 5, 3)

KoboldKoboldKobold 

KoboldKoboldKobold 

KoboldKoboldKobold 

KoboldKoboldKobold 

KoboldKoboldKobold

 

 

 

6.) Using what you learned in the previous question, write a function called text_triangle that takes an integer parameter and prints X’s in a triangle shape.

 

Here are some examples of calling the function with different arguments.  (The code executed is in blue, the output produced is in green):

 

text_triangle(3)

X 

XX 

XXX

 text_triangle(10)

X 

XX  XXX

XXXX

XXXXX

XXXXXX

XXXXXXX

XXXXXXXX

XXXXXXXXX

XXXXXXXXXX

 text_triangle(0)

 

 

There should be no spaces in front of each X.  The last one is the tricky one!  If the argument is <= 0, print one blank line.  Make sure you print the correct amount of X’s.

 

7.) Write a function called surface_area_of_cylinder that takes two arguments.  The first is a float representing the radius of a cylinder.  The second is a float representing the height of a cylinder.  The function calculates and prints the surface area of a cylinder with the given radius and height.  You will need to import the math module and use the math.pi constant.  The formula is:

 

SA = 2πr² + 2πrh

 

Here are some examples of calling the function with different arguments.  (The code executed is in blue, the output produced is in green):

 

surface_area_of_cylinder(10.0, 10.0)  surface_area_of_cylinder(0.0, 1.0)

The surface area of a cylinder with radius 10.0 and height 10.0 is 1256.6370614359173

The surface area of a cylinder with radius 0.0 and height 1.0 is

0.0

 

 

 

8.) The math module has a function called sqrt that returns the square root of its parameter.  It is used like this: math.sqrt(100).

 

Imagine you are flying a kite and the kite gets caught in the top of a perfectly straight palm tree.  The string pulls free from the kite leaving you with the full length of string and your kite stuck in the tree.  You measure the distance from you to the base of the tree.  Given the length of the kite string and the distance from you to the base of the tree you can calculate the height of the tree using the Pythagorean Theorem:

a² + b² = c²

 

In this case a is the distance from you to the tree, b is the unknown height of the tree, and c is the length of the kite string.

 

 

Write a function called tree_height that takes two arguments. The first is a float representing the distance from you to the base of the tree. The second is a float representing the length of the kite string. The function will calculate and print the height of the tree as shown in the examples below.  The function will calculate and print the height of the tree.

 

Here are some examples of calling the function with different arguments.  (The code executed is in blue, the output produced is in green):

 

tree_height(300, 500)

Kite string: 500 Distance: 300

Height: 400.0

 

 

 

 

tree_height(100, 141.421356)

Kite string: 141.421356 Distance: 100

Height: 99.99999966439368

 

• Since we are not using turtle graphics in this program, you will lose points if your main function still has (you don’t actually need a main function for this assignment):

 

input(‘Enter to end:’)

 

• Verify that your documentation makes sense and that you’ve added documentation to each of your

 

• Verify that your program works by running py.

 

• Upload your file to the Program 3 dropbox folder on D2L.

 

 

 

 

Part II: Shape Chooser (20 points)

 

Create a new file called shapechooser.py.  In the file write a program that does the following:

 

• Cut and paste the polygon function from hw2 into your module. Do not alter it.
• Ask the user how many polygons to draw.
• For each of the polygons perform the following steps:
  1. Ask the user how many sides the polygon should have.
  2. Ask the user for the color the polygon should be.
  3. Ask the user for the length of the side of the polygon.
  4. Using the values you got from the user, use a turtle and the polygon function to draw the polygon.
• User input is a string, so typecast when necessary.
• Here’s an example run (output is in green, input is in blue):

 

Enter the number of polygons you’d like to see: 3

Enter the number of sides:            4

Enter the color: red

Enter the side length for your polygon: 50

 

Enter the number of sides:           3  Enter the color: green

Enter the side length for your polygon: 100

 

Enter the number of sides:            5

Enter the color: blue

Enter the side length for your polygon: 200

 

Enter to end

 

• Here are screenshots from the run:

 

• Verify that your documentation makes sense and that you’ve added documentation to each  of  your
• Verify that your program works.
• Upload your file to the Hw3 assignments folder on D2L.