Common bugs from reference sharing in C Sharp (C#) - Mini Project: Build & Apply

Common Bugs from Reference Sharing in C#

📖 Scenario: Imagine you are working on a simple inventory system for a small store. You have a list of products, and you want to create a copy of this list to apply discounts without changing the original list.This project will help you understand how sharing references between objects can cause unexpected bugs.

🎯 Goal: You will create a list of products, then create a copy of this list. You will apply a discount to the copied list and observe how changes affect the original list due to reference sharing.

📋 What You'll Learn

Create a list of products with exact names and prices

Create a copy of the product list by assigning it to a new variable

Apply a discount to the copied list by changing product prices

Print both original and copied lists to observe the effect of reference sharing

💡 Why This Matters

🌍 Real World

Understanding reference sharing helps prevent bugs in programs that manage collections of objects, like inventory systems, user lists, or game entities.

💼 Career

Many programming jobs require managing data structures carefully to avoid unintended side effects from shared references, especially in object-oriented languages like C#.

1

Create the original product list

Create a list called products containing three Product objects with these exact values: ("Apple", 100), ("Banana", 50), and ("Cherry", 75). Use the provided Product class.

C Sharp (C#)

using System;
using System.Collections.Generic;

class Product
{
    public string Name;
    public int Price;

    public Product(string name, int price)
    {
        Name = name;
        Price = price;
    }
}

class Program
{
    static void Main()
    {
        // Create the products list with three Product objects
        // Your code here
    }
}

Need a hint?

Use new List<Product> { ... } and add three new Product(name, price) objects inside the braces.

2

Create a copy of the product list by reference

Create a new variable called discountedProducts and assign it the value of products (this copies the reference, not the objects).

C Sharp (C#)

using System;
using System.Collections.Generic;

class Product
{
    public string Name;
    public int Price;

    public Product(string name, int price)
    {
        Name = name;
        Price = price;
    }
}

class Program
{
    static void Main()
    {
        List products = new List
        {
            new Product("Apple", 100),
            new Product("Banana", 50),
            new Product("Cherry", 75)
        };
        
        // Create discountedProducts by assigning products
        // Your code here
    }
}

Need a hint?

Just assign discountedProducts = products; to copy the reference.

3

Apply a discount to the copied list

Use a for loop with variable i to go through discountedProducts and reduce each product's Price by 10%. Use integer division for simplicity.

C Sharp (C#)

using System;
using System.Collections.Generic;

class Product
{
    public string Name;
    public int Price;

    public Product(string name, int price)
    {
        Name = name;
        Price = price;
    }
}

class Program
{
    static void Main()
    {
        List products = new List
        {
            new Product("Apple", 100),
            new Product("Banana", 50),
            new Product("Cherry", 75)
        };
        
        List discountedProducts = products;
        
        // Apply 10% discount to each product in discountedProducts
        // Your code here
    }
}

Need a hint?

Use a for loop from 0 to discountedProducts.Count and update the Price by multiplying by 90 and dividing by 100.

4

Print both lists to observe the effect

Use two foreach loops to print the Name and Price of each product in products and discountedProducts. Print "Original products:" before the first list and "Discounted products:" before the second list.

C Sharp (C#)

using System;
using System.Collections.Generic;

class Product
{
    public string Name;
    public int Price;

    public Product(string name, int price)
    {
        Name = name;
        Price = price;
    }
}

class Program
{
    static void Main()
    {
        List products = new List
        {
            new Product("Apple", 100),
            new Product("Banana", 50),
            new Product("Cherry", 75)
        };
        
        List discountedProducts = products;
        
        for (int i = 0; i < discountedProducts.Count; i++)
        {
            discountedProducts[i].Price = discountedProducts[i].Price * 90 / 100;
        }
        
        // Print original and discounted products
        // Your code here
    }
}

Need a hint?

Use Console.WriteLine to print the headers and product details. Notice that both lists show the discounted prices because they share the same references.