Library Management System

A complete library management system implemented in C using doubly linked lists as the core data structure.

Features

Core Functionality

• Book Management: Add, update, delete, and search books
• Member Management: Register, manage, and track library members
• Loan Management: Handle book borrowing, returning, and renewals
• Search System: Advanced search capabilities across all data types
• Reporting: Generate various reports and statistics

Technical Features

• Doubly Linked List: Custom implementation with full CRUD operations
• Modular Architecture: Clean separation of concerns with repository, service, and UI layers
• Memory Management: Efficient memory usage with proper cleanup
• Input Validation: Comprehensive data validation throughout
• Error Handling: Robust error handling and reporting
• Test Framework: Complete test suite with unit and integration tests

Architecture

The system follows a layered architecture pattern:

┌─────────────────────────────────────┐
│           User Interface            │
├─────────────────────────────────────┤
│          Business Logic             │
│    (Services Layer)                 │
├─────────────────────────────────────┤
│          Data Access                │
│    (Repository Layer)               │
├─────────────────────────────────────┤
│         Core Data Structures        │
│    (Doubly Linked List)             │
└─────────────────────────────────────┘

Building and Running

Prerequisites

• GCC compiler (version 7.0+)
• Make utility
• Standard C library

Build Commands

# Basic build
make

# Debug build with AddressSanitizer
make debug

# Release build (optimized)
make release

# Run tests
make test

# Memory leak check
make memcheck

# Clean build artifacts
make clean

Running the Application

# Run the main application
./library_system

# Run tests
./test_runner

Usage

Main Menu Options

1. Book Management

   • Add new books to the library
   • Search for books by title, author, ISBN, or category
   • Update book information
   • View available books

2. Member Management

   • Register new library members
   • Search and view member information
   • Manage member status (active/suspended)
   • Track member loan history

3. Loan Management

   • Process book loans
   • Handle book returns
   • Manage loan renewals
   • Track overdue books and fines

4. Reports and Statistics

   • View library statistics
   • Generate various reports
   • Monitor system performance

Sample Data

The system includes sample data to demonstrate functionality:

• Sample books from programming and literature categories
• Test member accounts
• Example loan transactions

Data Models

Book

• ISBN (13-digit identifier)
• Title, Author, Publisher
• Publication year and category
• Copy management (total/available)
• Price and status

Member

• Unique member ID
• Personal information (name, contact)
• Membership type (Regular/Premium)
• Loan tracking and status

Loan

• Unique loan ID
• Member and book references
• Date tracking (loan/due/return)
• Fine calculation and status

File Structure

├── src/
│   ├── core/           # Core data structures
│   ├── models/         # Data models
│   ├── repositories/   # Data access layer
│   ├── services/       # Business logic
│   ├── ui/            # User interface
│   └── utils/         # Utilities
├── include/           # Header files
├── tests/             # Test suite
├── docs/              # Documentation
├── examples/          # Example code
└── Makefile          # Build configuration

Testing

The project includes a comprehensive test suite:

# Run all tests
make test

# Individual test categories
- Doubly Linked List operations
- Data model validation
- Repository CRUD operations
- Service layer business logic

Development Guidelines

Code Style

• Use ASCII characters only for maximum compatibility
• Follow consistent naming conventions
• Implement proper error handling
• Include comprehensive comments

Memory Management

• Always free allocated memory
• Use proper null checks
• Avoid memory leaks (verified with Valgrind)

Testing

• Write tests for all new functionality
• Maintain high test coverage
• Test both success and failure cases

Performance Characteristics

Time Complexity

• Insert/Delete: O(1) for known positions, O(n) for search
• Search: O(n) for linear search
• Sort: O(n log n) using merge sort

Space Complexity

• Memory usage scales linearly with data size
• Efficient memory pooling for frequent allocations

Extensibility

The modular design allows for easy extension:

• Add new data models
• Implement additional search algorithms
• Extend reporting capabilities
• Add file persistence
• Integrate with databases

Contributing

1. Follow the established code style
2. Write comprehensive tests
3. Update documentation
4. Ensure memory safety

License

This project is provided as an educational example. Feel free to use and modify for learning purposes.

ASCII-Only Design

This system is specifically designed to use only ASCII characters for maximum compatibility across different systems and environments. All text output, data validation, and user interfaces are ASCII-compliant.

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Built with C programming language and doubly linked lists for educational and practical library management.