IT 116: Introduction to Scripting

IT 116: Introduction to Scripting
Homework 7

Due
What You Need to Do
Setup On Your Machine
Specification
Functions
Test Code
Output
Suggestions
Testing on Your Machine
Copy the Script to Unix
Testing the Script on Unix (Optional)

Due

Sunday, March 30th at 11:59 PM

What You Need to Do

Create the script hw7.py
Make sure it obeys the rules in Rules for Homework Scripts
Move it to an an hw7 directory on pe15.cs.umb.edu

Setup On Your Machine

Open a text editor.
I would suggest the text editor built into the program IDLE.
Save the file as hw7.py

Specification

Your script must print an Inches to Centimeters conversion table between minimum and maximum values, and a Centimeters to Inches table also between a minimum and maximum values
You will find the conversion formulae here
Essentially, I want to do the same thing as you did in homework 6, but using functions
The script must have 5 functions
- get_int
- inches_to_centimeters_table
- inches_to_centimeters
- centimeters_to_inches_table
- centimeters_to_inches

Functions

get_int

Header
```
def get_int(prompt):
```
This function has one parameter, prompt a string
The function uses this prompt in a call to input to get a value
It converts this value into an integer and returns the converted value

inches_to_centimeters_table

Header

def inches_to_centimeters_table(min, max):

This function prints an Inches to Centimeters conversion table running from min_inches to max_inches
Before printing the table, the function prints the labels "Inches" and "Centimeters", followed by a line of dashes
This function prints each line of the table calling inches_to_centimeters to get the centimeter value
The centimeter values should align with the "Centimeters" label
See the example below

inches_to_centimeters

Header
```
def inches_to_centimeters(inches):
```
This function converts an inches value to centimeters and returns that value
The centimeter value must be an integer

centimeters_to_inches_table

Header

def centimeters_to_inches_table(min, max):

This function prints a centimeter to inches conversion table running from min_centimeters to max_centimeters
Before printing the table, the function prints the labels "Centimeters" and "Inches", followed by a line of dashes
The function creates the table calling centimeters_to_inches to get the inches value
The inches values should align with the "Inches" label
See the example below

centimeters_to_inches

Header
```
def centimeters_to_inches(centimeters):
```
This function converts a centimeter value to inches and returns that value
The inches value must be an integer

Test Code

Your script must contain the following statements

min_inches = get_int("Minimum inches: ")
max_inches = get_int("Maximum inches: ")
print()
inches_to_centimeters_table(min_inches, max_inches)
print()
min_centimeters = get_int("Minimum centimeters: ")
max_centimeters = get_int("Maximum centimeters: ") 
print()
centimeters_to_inches_table(min_centimeters, max_centimeters

They should appear at the bottom of your script

Output

The output should look something like this

Minimum inches: 1
Maximum inches: 10

Inches  Centimeters
-------------------
1       3
2       5
3       8
4       10
5       13
6       15
7       18
8       20
9       23
10      25

Minimum centimeters: 1
Maximum centimeters: 10

Centimeters Inches
------------------
1           0
2           1
3           1
4           2
5           2
6           2
7           3
8           3
9           4
10          4

The text in blue is what the user enters

Suggestions

Write this script in stages
Test your script at each step
Print the steps below
And check them off as you finish each one

Copy only the function headers for the five functions listed above into your script file.
Under each header, write pass.
Make sure this statement is indented.
Run the script.
Fix any errors you find.
Remove the pass statement from get_int.
Replace it with an assignment statement that uses input to give the variable number a value.
Use the parameter prompt as the argument to input.
Use an assignment statement to convert number into an integer.
Return number.
Copy the test code to the bottom of the script file.
Comment out all but the first two lines of the test code.
Run the script.
Fix any errors you find.
Remove the pass statement from inches_to_centimeters_table.
Replace it with a statement that prints the labels "Inches" and "Centimeters".
Then write a statement that prints a line of dashes, -.
Uncomment the next two lines in the test code.
Run the script.
Fix any errors you find.
Write a for loop that gives the loop variable inches values from min to max.
You will have to use range to do this, and be careful about the 2nd argument.
Inside the loop print the value of inches.
Run the script.
Fix any errors you find.
Add a second argument to the print statement in inches_to_centimeters_table.
This argument will be a call to the function inches_to_centimeters with inches as the argument.
Remove the pass statement from inches_to_centimeters.
Replace it with a statement that returns the parameter inches.
Run the script.
You should see two values for inches on each line.
Fix any errors you find.
Remove the return statement in inches_to_centimeters.
Replace it with an assignment statement that gives the variable cm the converted value of inches.
You will do this using the formula
```
cm = inches * 2.54
```
Turn the value of cm into an integer with an assignment statement using round.
Return the value of cm.
Run the script.
You should see both the inches and cm values on the same line.
Fix any errors you find.
Now you have to make sure the cm values align with the "Centimeters" label.
This can be done using the escape sequence for the tab character, \t.
Replace the space between "Inches" and "Centimeters" in the label with \t.
Now we need to print inches and cm with \t in between.
To make this work we will need to concatenate the three values.
But numbers cannot be concatenated with strings.
So we have to run the str string conversion function on both inches and cm.
Then we can use concatenation to put \t between them.
Run the script.
Fix any errors you find.
Repeat steps 3 - 7 for the last two function making appropriate changes.
Use the conversion formula
```
inches = centimeters * 0.39370079
```

Testing on Your Machine

Open IDLE
Use the Open command in IDLE to open hw7.py
Under the Run menu, select Run Module

Your output should look something like this

Minimum inches: 1
Maximum inches: 10

Inches  Centimeters
-------------------
1       3
2       5
3       8
4       10
5       13
6       15
7       18
8       20
9       23
10      25

Minimum centimeters: 1
Maximum centimeters: 10

Centimeters Inches
------------------
1           0
2           1
3           1
4           2
5           2
6           2
7           3
8           3
9           4
10          4

The entries in blue are user input.

Copy the Script to Unix

Open FileZilla and connect to pe15.cs.umb.edu
Go to your it116 directory
Go to your hw directory
Right-click in the whitespace inside the hw directory
Enter hw7 in the dialog box
Click and drag your script from the bottom left panel to the bottom right panel

Testing the Script on Unix (Optional)

Connect to pe15.cs.umb.edu using an ssh client like putty.exe (Windows) or ssh (Mac)
Go to the directory for this exercise
```
cd  it116/hw/hw7
```
Run this script
```
python3 hw7.py
```

You should see something like this

Minimum inches: 1
Maximum inches: 10

Inches  Centimeters
-------------------
1       3
2       5
3       8
4       10
5       13
6       15
7       18
8       20
9       23
10      25

Minimum centimeters: 1
Maximum centimeters: 10

Centimeters Inches
------------------
1           0
2           1
3           1
4           2
5           2
6           2
7           3
8           3
9           4
10          4

The text in blue is what you enter at the command line