File Structure and Debugging

Task

You will demonstrate your proficiency with file system operations, git version control, C programming, debugging, and GDB.

IMPORTANT

Before starting any tasks, run these commands in your workspace terminal:

bash .init_git_repos.sh
bash .pl_startup_script.sh

This will initialize the git repositories install necessary tools

Task 1 → Create Directory Structure

Create the following directory structure within ~/step1:

step1/
├── src/
│   └── main.c
├── lib/
│   └── my_libs.c
└── data/
    ├── 2021/
    │   └── grades.csv
    ├── 2022/
    │   └── grades.csv
    └── 2023/
        └── grades.csv

The files can be empty - they just need to exist in the structure

HINT

use mkdir -p for nested directories and touch to create empty files

Task 2 → Git Commit in Project Directory

The project directory is a git repository

1. Create a new file called README in the project directory
2. Add it to git
3. Make a commit with a message containing the string "skill demo" Click "Save and Grade"

Task 3 → Run Failing Tests

The buggy directory contains list_examples.c with bugs in the filter and merge functions

1. Navigate to the buggy directory
2. Run the tests: ./test.sh
3. Save the test output to ~/test-fail-output.txt Click "Save and Grade"

Task 4 → Fix Bugs and Verify

1. Fix the bugs in list_examples.c
   • There are 2 bugs in the code
2. Rerun the tests: ./test.sh
3. Save the successful output to ~/test-success-output.txt Click "Save the Grade"

Task 5 → Commit Bug Fixes

Make a git commit in the buggy direction with your bug fixes. The commit message must contain the string "fix bugs"

Task 6 → GDB Debugging - Find Malloc Size

The hash_demo directory contains hash_password.c

Using GDB

Debug the program:

$ cd hash_demo
$ gcc -g -o hash_password hash_password.c
$ gdb ./hash_password

Find the size passed to malloc for the hashed array in the simple_hash function (around line 15) Put this value in ~/hashed.txt Click "Save and Grade"

Task 7 → GDB Debugging - Find Array Value

Using the same program and GDB:

1. Set a breakpoint after the for loop completes (around line 28)
2. Run the program with: run Password123
3. Print the value of hashed[1]
4. Put this value in ~/hashed_index.txt

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Grading Notes

When grading, files are copied to /grade/student. If you sees an error about /grade/student/filename.txt, it means you didn’t create the file in ~/ in your workspace