Terminal Expense Tracker 📊

A robust, memory-safe command-line personal finance manager written entirely in C.

This project was built to demonstrate core computer science principles, including manual dynamic memory management, defensive programming, and binary file I/O operations.

✨ Features

• Dynamic Memory Allocation: Uses malloc and realloc to scale the transaction list infinitely while shrinking arrays upon deletion to conserve RAM.
• Defensive Programming: Strict input validation utilizing strtol and strtod to prevent crashes from invalid data types, alongside safeguards against corrupted binary data files.
• Binary File Persistence: Fast, automated saving and loading of structs directly to/from disk using fwrite and fread.
• Custom QuickSort: Manually implemented recursive QuickSort algorithm to order transactions by date or amount.
• Data Analysis: Generates calculated monthly summaries isolating net balances.

🛠️ Project Structure

cli-expense-tracker/
├── .github/
│   └── workflows/
│       └── make.yml         # "C/C++ CI with Make" workflow
├── src/
│   ├── main.c               # Application loop and interactive menu
│   ├── transaction.c        # Data models, QuickSort, and array management
│   ├── storage.c            # Binary File I/O operations
│   └── utils.c              # Safe string parsing and validation wrappers
├── data/
│   └── transactions.dat     # Auto-generated binary storage file
└── Makefile                 # Compilation instructions

🚀 Compilation & Installation

Prerequisites: You must have a C compiler (like gcc) and make installed on your system.

1. Clone the repository:

   git clone https://github.com/samybit/cli-expense-tracker.git
   cd cli-expense-tracker

2. Compile the project using the provided Makefile:

   make

3. Run the executable:

   ./expense_tracker

💻 Usage Examples

Upon running ./expense_tracker, you will be greeted with an interactive terminal menu.

Adding a Transaction:

Choose an option: 1
Enter date (YYYY-MM-DD): 2026-02-24
Enter amount: 150.50
Enter type (0 for INCOME, 1 for EXPENSE): 1
Enter category: Groceries
Enter description: Weekly food shopping
Transaction added successfully!

Viewing the Monthly Summary:

Choose an option: 4
Enter Year (e.g., 2023): 2026
Enter Month (1-12): 2

--- Summary for 2026-02 ---
Date         | Amount     | Type      | Category       
----------------------------------------------------
2026-02-24   | 150.50     | EXPENSE   | Groceries      
----------------------------------------------------
Total Income:  +0.00
Total Expense: -150.50
Net Balance:    -150.50
----------------------------------------------------

🧹 Cleanup

To remove the compiled object files and the executable, run:

make clean

(Note: This will not delete your saved transactions.dat data file).