IT 116: Introduction to Scripting

IT 116: Introduction to Scripting
Homework 8

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, April 6th at 11:59 PM

What You Need to Do

Create the script hw8.py
Make sure it obeys the rules in Rules for Homework Scripts
Make sure the script has a hashbang line and is executable

Setup On Your Machine

Open a text editor.
I would suggest the text editor built into the program IDLE.
Save the file as hw8.py

Specification

This script will create a file of pseudo_random numbers
And count the odd numbers in a text file
The script must contain 4 functions
- random_numbers_write
- count_odds
- largest_number

Functions

random_numbers_write

Header
```
def random_numbers_write(file):
```
This function has one parameter, file a file object for writing
It must create 10 pseudo-random numbers between 1 and 100
And write them to the file pointed to by file
The function should use the following algorithm

	looping 10 times:
	   create a random number between 1 and 1000
	   convert this number to a string
	   write this number to the file adding a newline

count_odds

Header
```
def count_odds(file):
```
This function has one parameter, file, a file object for reading
It should loop through the file and count the number of odd numbers it finds
And return this number
The function should use the following algorithm

	set odd_count to 0
	for each line in the file:
	   convert the line into an integer
	   if the number is odd:
	      add 1 to odd_count
	return odd_count

largest_number

Header
```
def largest_number(file):
```
This function has one parameter, file, a file object for reading
It should loop through the file to find the largest number
And return that number
The function should use the following algorithm

	set largest to 0
	for each line in the file:
	   convert the line into an integer
	   if this integer is greater than largest:
	      set largest to this number
	return largest

Test Code

Your script must contain the following statements

random.seed(67)
FILENAME = "numbers.txt"
file = open(FILENAME, "w")
random_numbers_write(file)
file = open(FILENAME, "r")
odds = count_odds(file)
print(odds)
file = open(FILENAME, "r")
max  = largest_number(file)
print(max)

They should appear at the bottom of your script

Output

The output should look something like this
```
7
99 
```

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

At the top of the script file import the random module.
Copy only the function headers for the four 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.
In random_numbers_write replace the pass statement with a for loop than runs 10 times.
Do this using a call to range with argument 10.
Inside the for loop use an assignment statement to create the variable number.
Give this variable a value by calling random.randint with arguments of 1 and 100.
Print number.
Copy the test code to the bottom of your script.
Comment out all but the first 4 lines.
Run the script.
Fix any errors you find.
Remove the print statement.
In the step above, you created 10 random integers.
You need to write those numbers to a file.
But you need to turn those numbers into strings, because we are creating text files.
Write an assignment statement that will turn number into a string.
Print number.
Run the script.
Fix any errors you find.
Remove the print in the for loop.
Replace it with a statement that will write number followed by a linefeed character, \n, to the file. You need the linefeed character so each number is written to its own line.
Run the script.
Look at the file numbers.txt .
It should contain the same numbers you saw in the previous step.
Fix any errors you find.
In count_odds remove the pass statement.
Set odd_count to 0.
Write a for loop that prints every line in file.
Uncomment the next two lines in the test code.
Run the script.
Fix any errors you find.
You need to convert each line in the file into a number.
Remove the print statement.
Replace it with a statement that creates the variable number by converting each line into an integer.
Print number.
Run the script.
Fix any errors you find.
Remove the print statement.
Replace it with an if statement that will run if number is odd.
If the remainder when you divide a number by 2 is 1, it is odd.
Inside the if statement add 1 to odd_count.
Print odd_count.
Run the script.
Fix any errors you find.
Remove the print statement.
Outside the for loop return odd_count.
Uncomment the next line in the test code.
Run the script.
Fix any errors you find.
Remove the pass statement from largest_number. Replace it with a statement that sets largest to 0.
Write a for loop that prints every line in the file.
Uncomment the next two lines in the test code.
Run the script.
Fix any errors you find.
Remove the print statement inside the for loop.
Replace it with a statement that creates the variable number by converting each line into an integer.
Print number.
Run the script.
Fix any errors you find.
Remove the print statement.
Replace it with an if statement that runs if number is greater than largest. Inside the if statement, set largest to number.
Print largest.
Run the script.
Fix any errors you find.
Remove the print statement.
Outside the for loop, return largest. Uncomment the last line in the test code. Run the script.
Fix any errors you find.

Testing on Your Machine

Open IDLE
Use the Open command in IDLE to open hw8.py
Run your script inside IDLE
Your output should look something like this
```
7
99
```

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 hw8 in the dialog box
Click and drag your script from the bottom left panel to the bottom right panel
Right-click on the file and select "Permissions" from the menu
Enter 755 in the box provided
This will make the script executable

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/hw8
```
Run this script
```
python3 hw8.py
```
You should see something like this
```
7
99
```