C Programming Practice Projects

A collection of practice projects created while learning C programming and systems programming.

📁 Projects

Project	What I Learned	Difficulty	Description
mycp	File handling, recursion	⭐⭐	Implementation of cp command
stack-calculator	Stack, algorithms	⭐⭐⭐	Calculator with parentheses support
json-parser	Parsing, memory management	⭐⭐⭐⭐	JSON parser and value extractor
mini-bash-like-shell	Processes, pipes	⭐⭐⭐⭐	Simple shell implementation
socket-server	Network programming	⭐⭐⭐⭐⭐	Multi-client chat server

🤔 What I Learned

Systems Programming

• File Operations: Low-level functions like open, read, write
• Processes: Fork child processes and exec other programs
• Pipes: Connect programs to exchange data
• Networking: Create servers and manage clients with sockets

Data Structures

• Stack: LIFO structure (used in calculator)
• String Parsing: Breaking text into meaningful tokens
• Trees: Storing JSON data in tree structures

C Language

• Pointers: Double pointers, function pointers, etc.
• Memory Management: Proper use of malloc/free
• Structures: Creating complex data structures
• Modularization: Organizing code into .h and .c files

🛠️ How to Run

Prerequisites

• Linux or macOS (or WSL)
• gcc compiler
• make

Building

# Run make in each directory
cd json-parser && make && cd ..
cd mini-bash-like-shell && make && cd ..
cd mycp && make && cd ..
cd socket-server && make && cd ..
cd stack-calculator && make && cd ..

Quick Testing

# 1. File copy tool test
echo "Hello World" > test.txt
./mycp/bin/mycp test.txt backup.txt

# 2. Calculator test  
echo "2 + 3 * 4" | ./stack-calculator/bin/calc

# 3. JSON parser test
echo '{"name": "test", "value": 42}' > test.json
./json-parser/bin/json-parser parse test.json

# 4. Shell test
./mini-bash-like-shell/bin/minishell
# In shell: echo "hello" | cat

# 5. Socket server test
./socket-server/bin/socket-server 8080 &
telnet localhost 8080

📖 Project Details

1. mycp - cp Command Implementation

./bin/mycp source.txt dest.txt      # Copy file
./bin/mycp source_dir/ dest_dir/    # Copy directory

Learned: File I/O, recursive directory traversal

2. stack-calculator - Calculator

./bin/calc
enter the expression: ( 2 + 3 ) * 4
result: 20

Learned: Stack data structure, expression evaluation algorithms

3. json-parser - JSON Parser

./bin/json-parser parse data.json           # Parse JSON
./bin/json-parser get data.json "user.name" # Extract specific value

Learned: String parsing, tree structures, memory management

4. mini-bash-like-shell - Shell Implementation

./bin/minishell
$ ls | grep txt > results.txt
$ cd /tmp && pwd
$ exit

Learned: Process creation, pipes, redirection

5. socket-server - Chat Server

./bin/socket-server 8080
# When client connects:
/nick Alice
Hello everyone!

Learned: Network programming, handling multiple clients concurrently

📁 Directory Structure

All projects follow a similar structure:

project/
├── src/           # .c source files 
├── include/       # .h header files
├── build/         # Compiled .o object files
├── bin/           # Final executables
├── Makefile       # Build configuration
└── README.md      # Documentation

Make Commands

make           # Compile
make clean     # Clean build files

💡 Helpful Resources

Useful learning resources:

• Learn C Programming - Interactive C tutorial
• C Programming Tutorial - Comprehensive C guide
• Beej's Guide to Network Programming - Socket programming made easy
• The Linux Programming Interface - Systems programming examples
• GeeksforGeeks C Programming - Practice problems and concepts

📝 Notes

• Started from C basics and gradually tackled more challenging projects
• Memory management was the most difficult part; pointers are still confusing
• Network programming turned out to be more interesting than expected