📒 Building a Simple Contact Book in C# – A Step-by-Step Guide

#csharp #programming

Managing contacts is a fundamental part of many applications. Whether you're organizing your friends, family, or work-related connections, having a simple system to store and manage contact information is essential.

In this tutorial, we’ll build a console-based Contact Book in C# from scratch. This project is perfect for beginners and covers important concepts such as:

✅ Object-Oriented Programming (OOP)
✅ Enums and Structs
✅ Working with Lists
✅ Implementing CRUD operations
✅ Interactive Console UI

🧱 Application Overview

Our application will include the following key components:

enum ContactType — To classify the type of contact (Friend, Family, etc.)
struct Contact — To define the structure of a contact
class AddressBook — To manage the contact list and operations
Main method — A console-based UI to interact with users

Let’s break it down step-by-step.

1️⃣ Contact Type Enum

This enum helps categorize each contact into meaningful groups.

enum ContactType
{
    Friend,
    Family,
    Professional,
    Other
}

2️⃣ Contact Struct

We define each contact using a simple struct that includes the contact's name, address, phone number, and type.

struct Contact
{
    public string Name { get; set; }
    public string Address { get; set; }
    public string PhoneNumber { get; set; }
    public ContactType Type { get; set; }

    public Contact(string name, string address, string phoneNumber, ContactType type)
    {
        Name = name;
        Address = address;
        PhoneNumber = phoneNumber;
        Type = type;
    }

    public override string ToString()
    {
        return $\"Name: {Name}\\nAddress: {Address}\\nPhone: {PhoneNumber}\\nType: {Type}\\n\";
    }
}

3️⃣ Address Book Class

This class manages a collection of contacts and provides methods for:

Adding new contacts
Editing existing contacts
Deleting contacts
Displaying all contacts
Filtering contacts by type

class AddressBook
{
    private List<Contact> contacts = new();

    public void AddContact(Contact contact) { ... }
    public void EditContact(string name, Contact updatedContact) { ... }
    public void DeleteContact(string name) { ... }
    public void ShowAllContacts() { ... }
    public void FilterContactsByType(ContactType type) { ... }
}

💡 Tip: We use List<Contact> for dynamic contact management and LINQ for filtering.

4️⃣ Console UI (Main Method)

We use a simple loop-driven console menu for user interaction. Here, users can perform all available operations step-by-step.

class Program
{
    static void Main()
    {
        AddressBook addressBook = new AddressBook();

        while (true)
        {
            Console.WriteLine(\"\\n📒 Contact Book Menu:\");
            Console.WriteLine(\"1. ➕ Add Contact\");
            Console.WriteLine(\"2. 📃 Show All Contacts\");
            Console.WriteLine(\"3. ✏️ Edit Contact\");
            Console.WriteLine(\"4. 🗑️ Delete Contact\");
            Console.WriteLine(\"5. 🔍 Filter Contacts by Type\");
            Console.WriteLine(\"6. ❌ Exit\");
            Console.Write(\"Choose an option (1-6): \");

            string choice = Console.ReadLine();
            // Logic for each menu option goes here...
        }
    }
}

🔍 Sample Output (Console UI)

📒 Contact Book Menu:
1. ➕ Add Contact
2. 📃 Show All Contacts
3. ✏️ Edit Contact
4. 🗑️ Delete Contact
5. 🔍 Filter Contacts by Type
6. ❌ Exit
Choose an option (1-6):

🚀 What You’ll Learn

By completing this project, you will gain practical experience with:

Structs and Enums
Collections (List<T>)
LINQ filtering
Input validation
Console application architecture

🌱 What’s Next?

Here are a few ideas to improve or expand the project:

📝 Save contacts to a file (JSON or CSV)
🔍 Add search functionality
🖼️ Build a GUI version using Windows Forms or WPF
🌐 Create a web version using ASP.NET

✅ Final Thoughts

This project is an excellent way to get hands-on with the fundamentals of C# and real-world coding patterns. It’s simple enough for beginners but flexible enough to grow into something more powerful.