Due: February 09 by 11:59pm

Submit: To submit this assignment, create a zip file of all the files in your R project folder for this assignment. Name the zip file`hw4-netID.zip`

, replacing`netID`

with your netID (e.g.,`hw4-jph.zip`

). Use this link to submit your file.

Weight: This assignment is worth 5% of your final grade.

Purpose: The purposes of this assignment are:

- To practice using conditional statements while writing functions in R.
- To practice the skill of writing and using test functions to understand the problem.
- To practice computational problem solving.

Assessment: Each question indicates the % of the assignment grade, summing to 100%. The credit for each question will be assigned as follows:

- 0% for not attempting a response.
- 50% for attempting the question but with
majorerrors.- 75% for attempting the question but with
minorerrors.- 100% for correctly answering the question.
The reflection portion is always worth 10% and graded for completion.

Rules:

- Problems marked
SOLOmay not be worked on with other classmates, though you may consult instructors for help.- For problems marked
COLLABORATIVE, you may work in groups of up to 3 students who are in this course this semester. You may not split up the work – everyone must work on every problem. And you may not simply copy any code but rather truly work together and submit your own solutions.

## Using the autograder

- You can check your solutions to problems 2 - 7 by logging into the autograder and uploading your
`hw4.R`

file.The file must be named`hw4.R`

or it won’t work.- Your user name is your netID, and your password is inside the
`readme.txt`

file in the Box folder I shared with you.

Download and use this template for your assignment. Inside the “hw4” folder, open and edit the R script called “hw4.R” and fill out your name, Net ID, and the names of anyone you worked with on this assignment.

Writing test functionsFor each of the following functions, write a test function first, and then write the function.

Your test functions will count for half of the available credit for each problem. Think carefully about the test cases to include in your test functions.

`guessAnimal(hasFourLegs, climbsTrees)`

[SOLO,
10%]Write the function `guessAnimal(hasFourLegs, climbsTrees)`

that returns a statement guessing an animal based on whether it has four
legs and whether it climbs trees. Here is the expected behavior:

`hasFourLegs` |
`climbsTrees` |
statement |
---|---|---|

`TRUE` |
`TRUE` |
“It’s probably a cat” |

`TRUE` |
`FALSE` |
“It’s probably a dog” |

`FALSE` |
`TRUE` |
“It’s probably a snake” |

`FALSE` |
`FALSE` |
“Hmm, I’m not sure” |

`isPositiveMultipleOf4Or7(n)`

[SOLO, 15%]Write the function `isPositiveMultipleOf4Or7(n)`

that
returns `TRUE`

if `n`

is a positive multiple of 4
or 7 and `FALSE`

otherwise. Note than `n`

could be
any data type.

`isEvenPositiveInt(x)`

[COLLABORATIVE, 20%]Given an arbitrary value `x`

, return `TRUE`

if
it is an integer, and it is positive, and it is even (all 3 must be
true), or `FALSE`

otherwise. If the value `x`

is
not an integer, the function should return `FALSE`

rather
than error. So, `isEvenPositiveInt("yikes!")`

returns
`FALSE`

, and `isEvenPositiveInt(123456)`

returns
`TRUE`

.

`isLeapYear(year)`

[SOLO, 20%]Write the function `isLeapYear(year)`

that returns
`TRUE`

if `year`

is a leap year and
`FALSE`

otherwise. Assume that `year`

is a
positive integer.

`getTheCents(n)`

[COLLABORATIVE, 20%]Write the function `getTheCents(n)`

which takes a value
`n`

that represents a payment in US dollars and returns the
number of cents in the payment. For example, if `n`

is
`2.45`

, the function should return `45`

. If
`n`

is an integer, the function should return `0`

,
as it has `0`

cents; if it isn’t a number, it should return
`NULL`

, because a non-number payment make no cents (ha!). If
the payment has partial cents (for example, `3.953`

), it
should be rounded to the nearest cent (in this case, `95`

cents).

Read and reflect on next week’s readings on iteration. Afterwards, in a comment
(`#`

) in your R file, write a short reflection on what you’ve
learned and any questions or points of confusion you have about what
we’ve covered thus far. This can just few a few sentences related to
this assignment, next week’s readings, things going on in the world that
remind you something from class, etc. If there’s anything that jumped
out at you, write it down.

Thursdays | 12:45 - 3:15 PM EST | Tompkins 208 | Dr. John Paul Helveston | jph@gwu.edu

LICENSE: CC-BY-SA