Smart Digital Phonebook (Agenda Digital)

A CLI-based contact management system developed in C that demonstrates the practical use of singly linked lists, dynamic memory allocation, and file persistence.

📋 Features

• Dynamic Contact Management: Add, remove, and search for contacts by name using a linked list structure.
• Data Persistence: Automatically loads data from agenda.txt at startup and saves all changes upon exiting.
• Manual Reordering: Allows users to swap the positions of two contacts within the list while maintaining pointer integrity.
• Input Validation: Includes specific logic to validate phone number formats (XX XXXXXXXXX) and email addresses (checking for the @ symbol).
• Safety Backups: Generates a agenda_backup.txt before overwriting the main database to prevent data loss.
• Memory Efficiency: Implements a cleanup function to free all allocated RAM before the program terminates.

🛠️ Technical Details

• Language: C.
• Data Structure: Singly Linked List (struct Contato).
• Key Algorithms:
  • Node insertion at the end of the list.
  • Pointer manipulation for node swapping (reordering).
  • Sequential search for contact retrieval.

🚀 How to Run

1. Clone the repository:

   git clone [https://github.com/your-username/your-repo-name.git](https://github.com/your-username/your-repo-name.git)
   cd your-repo-name

2. Compile the project: You can use gcc to compile the source files:

   gcc phonebook.c funcoes.c -o phonebook

3. Run the application:

   ./phonebook

📁 Project Structure

• phonebook.c: Contains the main execution loop and menu logic.
• funcoes.c: Implementation of all core features (CRUD, sorting, file I/O).
• funcoes.h: Header file containing the Contato struct definition and function prototypes.

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Developed by: Enzo Giacomin & Pedro Henrique Mognon De Bortoli.