# Initialize Otter
import otter
grader = otter.Notebook("hw5-branching.ipynb")

🏡📝 Homework 5

This assignment includes three problems on the topic of branching.

Question 1: Grade Calculator

Your task is to write a function accepts an integer score and returns a string of the letter grade that score corresponds to. The mapping of score ranges to letter grades is:

Score	Letter Grade
95-100	A+
90-94	A
80-89	B+
70-79	B
60-69	C+
50-59	C
0-49	F

(Important note: This is just an example, not the letter grade mapping for this course.)

Write python code to do the following:

• Define a function called letter_grade which accepts one input argument, an integer score s

• Implement your function so that it returns the proper letter grade for an input score

• You may assume the input s is an integer, but if s is outside the bounds \([0, 100]\), your function should return the message: "invalid score"

Your code replaces the prompt: ...

...

grader.check("q1-grade-calculator")

Question 2: Leap Year

A year in the modern Gregorian Calendar consists of 365 days. In reality, the earth takes longer to rotate around the sun. To account for the difference in time, every 4 years, a leap year takes place. A leap year is when a year has 366 days: An extra day, February 29th. The requirements for a given year to be a leap year are:

1. The year must be divisible by 4

2. If the year is a century year (1700, 1800, etc.), the year must be evenly divisible by 400

Some examples:

• 1600, 1712, and 2016 are all leap years

• 2002 is not a leap year (not divisible by 4)

• 1900 is not a leap year (1900 is a century year not divisible by 400)

Your task is to code a function that identifies whether or not a year is a leap year.

Write python code to do the following:

• Define a function called is_leap_year which accepts one input argument, an integer year y

• Implement your function so that it returns True if the the year y is a leap year and otherwise returns False

Your code replaces the prompt: ...

...

grader.check("q2-leap-year")

Question 3: Seasons

The date ranges for the seasons are as follows:

Season	Date Range
spring	March 20 - June 20
summer	June 21 - September 21
autumn	September 22 - December 20
winter	December 21 - March 19

Your task is to write a function that takes in a date and returns the season that the date falls in.

Write python code to do the following:

• Define a function called get_season that takes as input arguments a string m and an integer d

• The function should determine the season the date given by month m and day d

  • For example, if m = "march" and d = 27, the function should return “spring”

• You must check that m and d form a valid date. If not, return “invalid”

You may assume the month m is in all lowercase

Your code replaces the prompt: ...

...

grader.check("q3-seasons")