A document from MCS 275 Spring 2022, instructor David Dumas. You can also get the notebook file.

# MCS 275 Spring 2022 Homework 13 Solutions¶

• Course Instructor: David Dumas
• Solutions prepared by: Johnny Joyce

## Instructions:¶

• Complete the problems below, which ask you to write Python scripts.

This homework assignment must be submitted in Gradescope by Noon central time on Tuesday 19 April 2022.

### Collaboration¶

Collaboration is prohibited, and you may only access resources (books, online, etc.) listed below.

### Resources you may consult¶

These things might be helpful while working on the problems. Remember that for worksheets, we don't strictly limit what resources you can consult, so these are only suggestions.

### Point distribution¶

This homework assignment has two problems. The grading breakdown is:

Points Item
6 Problem 2
2 Problem 3
14 Total

The part marked "autograder" reflects points assigned to your submission based on some simple automated checks for Python syntax, etc.. The result of these checks is shown immediately after you submit.

### What to do if you're stuck¶

Ask your instructor or TA a question by email, in office hours, or on discord.

## Problem 2 - Flask divisors¶

Write a Flask application that takes an integer given as part of the URL and returns a page listing the divisors of the integer and whether it is prime or composite.

Specifically, the app should respond to a request such as

/divisors/of/7/
/divisors/of/18/
/divisors/of/832/

or anything of the general form /divisors/of/<N>/ where N is a positive integer greater than one, and generate an HTML document with:

• A title "The divisors of N"
• An unordered list whose items are the positive integers that divide N, starting with 1 and ending with N.
• A paragraph reading either "The integer N is composite." or "The integer N is prime." depending on whether there are more than 2 divisors or exactly 2 divisors, respectively. The last word in the sentence should be given strong emphasis. Here, each N must of course be replaced by whatever integer is specified as part of the URL.

For example, running the app and then loading http://localhost:5000/divisors/of/18/ in a browser (perhaps changing 5000 to the port number Flask reports it is using when it starts up) should produce a page looking something like this:

### Hints¶

The point of the problem is to show you can generate HTML in a Flask application, so here's some advice to make the mathematical side easier.

You can just iterate through all the integers k between 1 and N and check whether each one is a divisor of N or not. This problem does not require you to use a more efficient method.

An integer k between 1 and N is a divisor of N exactly when N%k == 0.

In [ ]:

@app.route("/divisors/of/<N>/")
def divisors(N):
'''Given integer N, generates webpage with divisors of N and states whether or not N is prime'''

N = int(N)

divisors = []
for k in range(1,N+1): # Get a list of all divisors
if N % k == 0:
divisors.append(k)
# Alternatively: divisors = [k for k in range(1,N+1) if N % k == 0]

# Create header and opening tags for HTML code
html = '''
<!doctype HTML>
<html>
<title>The divisors of {0}</title>
<body>
<h1>The divisors of {0}</h1>
<ul>
'''.format(N)

# Put each divisor in an li tag
for divisor in divisors:
html += "<li>{}</li>".format(divisor)

# End unordered list and put a header for next section
html += '''
</ul>
<h1>Classification of {}</h1>
'''.format(N)

# Paragraph for if n is prime or composite
if len(divisors) == 2:
html += "<p>The integer {} is <b>prime</b></p>".format(N)
else:
html += "<p>The integer {} is <b>composite</b></p>".format(N)

# Close out of any remaining tags
html += '''
</body>
</html>
'''

return html

app.run()