Assignment 2: Learn to C

Due Friday, January 31, before midnight

The goals for this assignment are:

Work with strings
Work with structs
Work with arrays

1. Update your repository

Do a fetch upstream to obtain the basecode for this assignment.

The first time you do a fetch, you need to set the URL of the upstream repository.

git remote add upstream git@github.com:brynmawr-cs223-s25/cs223-s25-assignments.git

Using the command line

Open terminal and change your current directory to your assignment repository.
Run the command git fetch upstream
Run the command git merge upstream/main

Your repository should now contain a new folder named A02.

The fetch and merge commands update your repository with any changes from the original.

2. Bad password

Write a program, password.c, that asks the user for a word and creates a bad password from it. You can assume that all characters are lowercase.

$ make password
gcc password.c -o password
$ ./password
Enter a word: elephant
Your bad password is 313ph@nt
$ ./password
Enter a word: hello
Your bad password is h311o
$ ./password
Enter a word: rhythm
Your bad password is rhythm

Your bad password algorithm should

Replace 'e’s with '3’s
Replace 'l’s with '1’s
Replace 'a’s with '@'s

3. Snackbar

Write a program, snackbar.c, that maintains a list of snacks available for purchase.

$ make snackbar
gcc snackbar.c -o snackbar

$ ./snackbar
Welcome to Steven Struct's Snack Bar.

How much money do you have? 5

0) Coco Puffs           cost: $1.50     quantity: 4
1) Manchego cheese      cost: $15.50    quantity: 6
2) Magic beans          cost: $0.50     quantity: 0

What snack would you like to buy? [0,1,2] 1
You can't afford it!

$ ./snackbar
Welcome to Steven Struct's Snack Bar.

How much money do you have? 5

0) Coco Puffs           cost: $1.50     quantity: 4
1) Manchego cheese      cost: $15.50    quantity: 6
2) Magic beans          cost: $0.50     quantity: 0

What snack would you like to buy? [0,1,2] 2
Sorry, we are out of Magic beans

$ ./snackbar
Welcome to Steven Struct's Snack Bar.

How much money do you have? 5

0) Coco Puffs           cost: $1.50     quantity: 4
1) Manchego cheese      cost: $15.50    quantity: 6
2) Magic beans          cost: $0.50     quantity: 0

What snack would you like to buy? [0,1,2] 0
You bought Coco Puffs
You have $3.50 left

Requirements:

Your program should define a struct snack that stores a name, cost, and quantity
Your program should define at least three snacks and store them in an array
Your program should be similar to the given output but feel free to customize it!

4. Shift Cypher

Write a program, cypher.c, that asks the user for a word and then encodes it using a shift cypher. A shift cypher replaces each letter with a letter that is X positions from it in the alphabet. For example, is the letter is 'a' and the shift is 2, we replace 'a' with a 'c'. You can assume that all inputs are lowercase and do not contain special characters.

$ make cypher
gcc cypher.c -o cypher
$ ./cypher
Enter a word: elephant
Enter a shift: 2
Your cypher is gngrjcpv
$ ./cypher 
Enter a word: gngrjcpv
Enter a shift: -2
Your cypher is elephant
$ ./cypher 
Enter a word: hello
Enter a shift: 7
Your cypher is olssv
$ ./cypher 
Enter a word: a
Enter a shift: -2
Your cypher is y
$ ./cypher 
Enter a word: z
Enter a shift: 2**
Your cypher is b

Hints:

Recall that characters as represented as digits in ASCII. A straight-forward implementation can add offsets to each character of the word.

5. Submit your Work

Push you work to Github to submit your work.

$ cd A02
$ git add *.c
$ git commit -m "assignment 2 complete"
$ git push

6. Grading Rubric

Assignment rubrics

Grades are out of 4 points.

(1 point) password
- (0.1 points) style and header comment
- (0.4 points) correct behavior: asks the user for input and creates the new string
- (0.5 points) no memory errors
(1 point) cypher
- (0.1 points) style and header comment
- (0.4 points) correct behavior: asks the user for input and creates the new string
- (0.5 points) no memory errors
(2 points) snackbar
- (0.2 points) style and header comment
- (0.8 points) correct behavior
- (1.0 points) no memory errors

Code rubrics

For full credit, your C programs must be feature-complete, robust (e.g. run without memory errors or crashing) and have good style.

Some credit lost for missing features or bugs, depending on severity of error
-12.5% for style errors. See the class coding style here.
-50% for memory errors
-100% for failure to checkin work to Github
-100% for failure to compile on linux using make