Assignment 1: Introduction to C

Click this link to clone the repository: Assignment1-Intro-to-C

Overview

In this first assignment, you will get your system set up to be able to compile and run C programs, begin to familiarize yourself with the C programming language (we will use C throughout this term), and apply some of what you have learned about how your computer represents numbers.

Set Up Your Environment

Some general instructions for getting up and running with C on your computer are provided below. However, at this point in the program, we expect that you will be able to figure out some of the details yourself. If you get stuck, please reach out on Discord!

Windows 10 or 11

Mingw is a Windows runtime environment for GCC, GDB, make and related binutils. To install mingw, open up a Windows Terminal and run the following scoop command. This assumes that you already have scoop installed. If you don't, following the instructions at scoop.sh to install it.

> scoop install mingw

OS X

Install gcc and gdb using brew. If you don't have brew installed, first following the instructions at brew.sh to install it.

> brew install gcc
> brew install gdb

Alternatives: Linux Virtual Machine, Dual Boot, or WSL

The GNU tools work particularly well in Linux, Unix, and FreeBSD -based environments. If you are running Windows, you can get up and running with a full Linux environments a number of different ways. Refer to the following article for information about those options How to Install Ubuntu on Windows.

Test Your Setup

  1. Next, let's test your setup to make sure that everything is installed properly. Create a file that contains the following basic C program. You may use whatever editor you chose (e.g., notepad, emacs, vi, VSCode, etc.). Name your file hello.c.

    #include <stdio.h>

int main() {
   printf("Hello, World!\n");
   return 0;
}

  2. From within your shell, make sure that you have navigated to the directory containing the file you just created and run the following commands:

    > gcc hello.c -o hello

    This command uses the gcc compiler to compile your C program into an executable called hello. You can now run your compiled program as follows:

    > ./hello

    If all goes well, your program should print out the message "Hello, World!" to the prompt. If all didn't go well, please post your errors or questions to the course's Discord Channel.

Assignment

Objective:

Develop a C program to parse command-line arguments and determine if they match specific patterns. This assignment is designed to introduce you to C while applying some of what you have learned about number representations and challenge your problem-solving skills.

Task:

Implement a program in ANSI C that takes command-line arguments and checks if each argument matches a specific pattern based on a command-line flag: -x, -y, or -z, with -x being the default. The program should handle a -v flag for a variant output.

Output:

By default, the program prints “match” for each argument that matches the pattern and “nomatch” for those that do not, each on a separate line. If the -v flag is provided, the program instead performs a transformation on matching arguments (specified below) and prints nothing for non-matching arguments.

Flags:

  • At most one of -x, -y, or -z can be provided.
  • The -v flag can appear before or after the pattern flag.
  • All flags precede other command-line arguments.
  • Non-flag arguments do not start with -.
  • All arguments are in ASCII.

Patterns and Conversions:

  • -x mode:

    • Match a sequence of alternating digits and letters (e.g., 1a2b3), ending with a digit.
    • For matches with -v, convert each character to its ASCII value.
    • Example: 1a2b → 1-97-2-98-3

  • -y mode:

    • Match any string where the sum of ASCII values of all characters is a prime number.
    • For matches with -v, convert the string into its hexadecimal ASCII representation.
    • Example: abb (sum = 293, not a prime number) → 61-62-62

  • -z mode:

    • Match strings that form a valid arithmetic expression using digits and +, -, *, / (e.g., 12+3-4).
    • For matches with -v, print the number of + operations, followed by the number of - operations, followed by the number of * operations, followed by the number of \ operations.
    • Example: 12+3-4 → 1100
    • Note that depending on your shell, you may have to surround the expression with quotes when passing it through the command line. In Unix-like shells, * is interpreted as a wildcard character.

Constraints:

  • Compile without errors using gcc with no extra flags.
  • Do not depend on libraries other than the standard C library.
  • Do not use regex.h, multiplication, division, or modulo operators. Bitwise operations are allowed.
  • Hand in a single assignment1.c file.

Examples:

$ ./assignment1 -x 1a2b3
match
$ ./assignment1 -x -v 1a2b3
1-97-2-98-3
$ ./assignment1 -y abb
match
$ ./assignment1 -z 12+3-4
match
$ ./assignment1 -z "1+2*3*2"
1020

Grading

Total Points: 70

  1. Correctness and Functionality (55 Points)

    • Pattern Matching (-x, -y, -z) (45 points)
      • Correctly identifies matching and non-matching patterns for each mode. (15 points per mode)
    • Transformation with -v Flag (10 points)
      • Correctly performs the specified transformations for matching patterns.

  2. Code Quality and Style (10 Points)

    • Readability and Comments (5 points)
      • Code is well-organized and readable with clear, concise comments explaining complex logic.
    • Conventions and Syntax (5 points)
      • Consistent naming conventions and adherence to standard C syntax and idiomatic practices.

  3. Efficiency (5 Points)

    • Algorithmic Efficiency (5 points)
      • Uses efficient solutions and avoids unnecessary computations.

Submitting Your Work

Your work must be submitted Anchor for degree credit and to Gradescope for grading.

  1. Ensure that you commit and push your local code changes to your remote repository. (Note: In general, you should commit and push frequently, so that you have a backup of your work, so that there is evidence that you did your own work, and so that you can return to a previous state easily.)
  2. Upload your submission to Gradescope via the appropriate submission link by selecting the correct GitHub repository from the drop-down list.
  3. Export a zip archive of your GitHub repository by visiting your repo on GitHub, clicking on the green Code button, and selecting "Download Zip".
  4. Upload the zip file of your repository to Anchor using the form below.