📒 Address Book Application

A terminal-based Address Book Management System written in pure C with file persistence, modular programming, contact validation, and interactive CLI menus.

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📌 What is this Project?

The Address Book Application is a menu-driven terminal application developed using the C programming language.

It allows users to:

• Create contacts
• Search contacts
• Edit contact details
• Delete contacts
• List all contacts
• Save contacts permanently using CSV file handling

The application demonstrates core system programming concepts such as:

• Structures
• File handling
• Modular programming
• Input validation
• String handling
• Dynamic menu systems

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🗂️ Project Structure

AddressBook-Application/
├── main.c          # Main menu system and navigation
├── contact.c       # Contact operations and validation logic
├── contact.h       # Structures, constants, function declarations
├── file.c          # File save/load operations
├── file.h          # File handling declarations
├── populate.c      # Dummy contact population
├── populate.h      # Populate function declaration
├── Makefile        # Build automation
├── contact.csv     # Persistent contact storage
├── .gitignore      # Git ignored files
└── README.md       # Project documentation

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⚙️ Features

Contact Management

• Add new contacts
• Edit existing contacts
• Delete contacts
• Search contacts

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Search Modes

Search contacts using:

• Name
• Phone Number
• Email Address

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Validation System

The application validates:

• Empty input
• Invalid names
• Invalid phone numbers
• Invalid email addresses
• Duplicate phone numbers
• Duplicate emails

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File Persistence

Contacts are automatically stored using CSV file handling.

Even after closing the application, contact data remains saved.

Example:

John Doe,9876543210,john@gmail.com
Alice Smith,9123456780,alice@gmail.com

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🖥️ Terminal UI

The project uses ANSI escape sequences for:

• Colored menus
• Better readability
• Highlighted errors
• Success messages
• Structured terminal tables

Example:

==================================================
                ADDRESS BOOK SYSTEM
==================================================

1. Create Contact
2. List Contacts
3. Search Contact
4. Edit Contact
5. Delete Contact
6. Save Contacts
7. Exit

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🔄 Application Flow

Start Program
      ↓
Load Contacts From CSV
      ↓
Display Main Menu
      ↓
User Selects Operation
      ↓
Perform Validation
      ↓
Execute Contact Operation
      ↓
Auto Save to CSV
      ↓
Return to Menu

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🚀 Getting Started

Prerequisites

• GCC Compiler
• Linux / Unix Environment
• Terminal with ANSI color support

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⚒️ Build Project

Using Makefile

make

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Manual Compilation

gcc main.c contact.c file.c populate.c -Wall -Wextra -Werror -std=c11 -o addressbook

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▶️ Run the Application

Linux / Mac

./addressbook

Windows

addressbook.exe

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🧹 Clean Build Files

make clean

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🔁 Rebuild Project

make rebuild

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📋 Core Concepts Demonstrated

Concept	Usage
Structures	Contact data management
File Handling	CSV storage
String Functions	Search and validation
Arrays	Contact storage
Modular Programming	Separate source modules
ANSI Escape Codes	Colored terminal UI
Input Validation	User safety checks
Makefile	Build automation

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📂 Contact Structure

typedef struct
{
    char name[50];
    char phone[20];
    char email[50];
} Contact;

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🔍 Search Functionality

The application supports:

• Partial name matching
• Exact phone matching
• Email-based lookup

Example:

Search by Name → "John"
Matches:
- John Doe
- Johnson Mark

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⚠️ Limitations

• Fixed maximum contacts (MAX_CONTACTS = 100)
• Terminal-only interface
• CSV storage only
• Single-user application

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🚀 Future Improvements

• Contact sorting
• Password protection
• Binary file storage
• Case-insensitive search
• Import/export support
• Contact categories
• GUI version
• Dynamic memory allocation

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👨‍💻 Author

Santhosh Pandian SG
Embedded Systems Engineer | Emertxe ECEP Trainee

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📄 License

This project is licensed under the MIT License.