DotNet basics: What is Spaghetti Code?

Spaghetti code is a term developers use to describe code that’s messy, tangled, and hard to follow. It often grows without structure and becomes a pain to work with—especially when you're trying to add new features or fix bugs.

What causes spaghetti code?

• Large classes and methods
• Multiple responsibilities in one class
• Using the goto keyword
• Bad naming
• Magic numbers
• Code repetition

An example

public class OrderProcessor
{
    public void ProcessOrder()
    {
        Console.WriteLine("Enter product ID:");
        int productId = int.Parse(Console.ReadLine());

        Console.WriteLine("Enter quantity:");
        int quantity = int.Parse(Console.ReadLine());

        double price = 0;
        if (productId == 1)
            price = 10.99;
        else if (productId == 2)
            price = 15.49;
        else if (productId == 3)
            price = 5.25;

        double total = price * quantity;

        Console.WriteLine("Do you want express shipping? (y/n)");
        string shipping = Console.ReadLine();

        if (shipping == "y")
        {
            total += 5.0;
        }

        Console.WriteLine("Order Summary:");
        Console.WriteLine("Product ID: " + productId);
        Console.WriteLine("Quantity: " + quantity);
        Console.WriteLine("Total Price: $" + total);

        Console.WriteLine("Saving order...");
        Console.WriteLine("Order saved.");
    }
}

What’s wrong here?

• One class is doing everything
• Magic numbers everywhere
• No reuse or structure
• Not easy to test or maintain

A cleaner, more structured version

public class ProductService
{
    public double GetPrice(int productId)
    {
        return productId switch
        {
            1 => 10.99,
            2 => 15.49,
            3 => 5.25,
            _ => throw new ArgumentException("Invalid product ID")
        };
    }
}

public class Order
{
    public int ProductId { get; set; }
    public int Quantity { get; set; }
    public bool ExpressShipping { get; set; }

    public double CalculateTotal(double pricePerItem)
    {
        double total = pricePerItem * Quantity;
        if (ExpressShipping)
        {
            total += 5.0;
        }
        return total;
    }
}

public class OrderUI
{
    private readonly ProductService _productService = new();

    public void Run()
    {
        var order = new Order();

        Console.WriteLine("Enter product ID:");
        order.ProductId = int.Parse(Console.ReadLine());

        Console.WriteLine("Enter quantity:");
        order.Quantity = int.Parse(Console.ReadLine());

        Console.WriteLine("Do you want express shipping? (y/n)");
        order.ExpressShipping = Console.ReadLine()?.ToLower() == "y";

        double price = _productService.GetPrice(order.ProductId);
        double total = order.CalculateTotal(price);

        Console.WriteLine($"
Order Summary:");
        Console.WriteLine($"Product ID: {order.ProductId}");
        Console.WriteLine($"Quantity: {order.Quantity}");
        Console.WriteLine($"Total Price: ${total}");

        Console.WriteLine("Saving order...");
        Console.WriteLine("Order saved.");
    }
}

Why this is better

• Each class handles one job
• It’s easier to follow and test
• We can reuse the logic later

Other code smells

• Ravioli code – Each class is clean, but there are so many tiny parts that the overall structure gets confusing.
• Lasagna code – Too many tightly coupled layers. Changing one breaks everything else.

---

Question - How do you avoid writing messy, tangled, and hard to follow code?