Cart design
- C# course
- Beginner
- Lesson 48/116
- 6 min
Design the shopping cart class skeleton and the product model.
Cart design
In this project we will build a shopping cart application step by step. The first step is to design the Product class that represents an item in the cart.
A product has three core properties: name (string), price (double) and quantity (int). In C# we write these as auto properties using public ... { get; set; }. They can then be accessed as p.Name from outside.
Auto property
In C#, writing public string Name { get; set; } creates an auto property. The compiler generates a hidden field behind the scenes; you do not write the get/set body.
This is very handy for classes that simply carry data. You can build the object shortly with var p = new Product { Name = "Pen", Price = 12.5, Quantity = 2 };; this form is called an object initializer.
Practice Define the Product class
Define a Product class. It must have three auto properties: public string Name, public double Price, public int Quantity (each with { get; set; }). Main already builds a Product and prints its name; you only write the class.
Starter code
using System;
// Define the Product class here
class Program
{
static void Main()
{
var p = new Product { Name = "Pen", Price = 12.5, Quantity = 2 };
Console.WriteLine(p.Name);
}
}Sample solution
using System;
class Product
{
public string Name { get; set; }
public double Price { get; set; }
public int Quantity { get; set; }
}
class Program
{
static void Main()
{
var p = new Product { Name = "Pen", Price = 12.5, Quantity = 2 };
Console.WriteLine(p.Name);
}
}Expected output
Pen
Questions and answers
Review the lesson questions together with their answers. To test yourself, solve the lesson interactively.
1 Which data structure fits a cart best?
// several products in a cart- A single int variable
- A list holding Product objects Correct answer
- A single string variable
- A bool variable
Explanation: You hold several Product objects in a List<Product>.
2 Write the class name
class ____
{
public string Name { get; set; }
public double Price { get; set; }
public int Quantity { get; set; }
}class Product
{
public string Name { get; set; }
public double Price { get; set; }
public int Quantity { get; set; }
}Explanation: Class names are PascalCase and start with a capital letter.
3 Match each property name to its type
| Term | Meaning |
|---|---|
Name |
string |
Price |
double |
Quantity |
int |
items |
List<Product> |