**Course Title:** Mastering Go: From Basics to Advanced Development **Section Title:** Working with Data Structures: Arrays, Slices, and Maps **Topic:** Create a program that uses arrays, slices, and maps effectively.(Lab topic) **Introduction:** In this lab topic, we will apply the concepts learned from previous topics to create a program that effectively uses arrays, slices, and maps. We will design a simple e-commerce application that stores product information, shopping cart data, and order details using these data structures. By the end of this topic, you will have hands-on experience working with arrays, slices, and maps and understand how to choose the best data structure for a given problem. **Lab Program: E-commerce Application** **Step 1: Define the Requirements** Our e-commerce application will have the following features: * Product catalog: A list of products with their IDs, names, prices, and quantities. * Shopping cart: A collection of products added by the user. * Order details: Data about the user's orders, including the order ID, user ID, order date, and order total. **Step 2: Design the Data Structures** Based on the requirements, we will design the following data structures: * **Product Catalog:** An array of structs to store product information. * **Shopping Cart:** A slice of structs to store products added by the user. * **Order Details:** A map to store order data with the order ID as the key. **Step 3: Implement the Program** ```go package main import "fmt" // Define a struct to represent a product type Product struct { ID int Name string Price float64 Quantity int } // Define a struct to represent an order type Order struct { ID int UserID int OrderDate string OrderTotal float64 } func main() { // Create a product catalog as an array of structs productCatalog := [3]Product{ {1, "Product 1", 19.99, 10}, {2, "Product 2", 9.99, 20}, {3, "Product 3", 29.99, 5}, } // Create a shopping cart as a slice of structs shoppingCart := make([]Product, 0) // Add a product to the shopping cart shoppingCart = append(shoppingCart, productCatalog[0]) // Create an order details map orderDetails := make(map[int]Order) // Add an order to the order details map orderDetails[1] = Order{1, 1, "2023-03-01", 19.99} // Print the product catalog fmt.Println("Product Catalog:") for _, product := range productCatalog { fmt.Printf("ID: %d, Name: %s, Price: %.2f, Quantity: %d\n", product.ID, product.Name, product.Price, product.Quantity) } // Print the shopping cart fmt.Println("\nShopping Cart:") for _, product := range shoppingCart { fmt.Printf("ID: %d, Name: %s, Price: %.2f, Quantity: %d\n", product.ID, product.Name, product.Price, product.Quantity) } // Print the order details fmt.Println("\nOrder Details:") for orderID, order := range orderDetails { fmt.Printf("Order ID: %d, User ID: %d, Order Date: %s, Order Total: %.2f\n", orderID, order.UserID, order.OrderDate, order.OrderTotal) } } ``` **Step 4: Run the Program and Analyze the Output** Run the program and observe the output. The program displays the product catalog, shopping cart, and order details. **Key Takeaways:** * Arrays are suitable for storing a fixed number of elements of the same type. * Slices are dynamic arrays that can grow or shrink in size as elements are added or removed. * Maps are useful for storing key-value pairs where each key is unique. * Choosing the right data structure depends on the specific requirements of the problem. **Best Practices:** * Use arrays when you know the exact number of elements beforehand. * Use slices when you need a dynamic array that can change size. * Use maps when you need to store key-value pairs with unique keys. **External Resources:** * The official Go documentation provides detailed information on arrays, slices, and maps: [https://go.dev/ref/spec#Slice_types](https://go.dev/ref/spec#Slice_types) * The Go standard library offers various functions for working with arrays, slices, and maps: [https://pkg.go.dev/std](https://pkg.go.dev/std) **Need Help or Want to Discuss Further?** If you have questions or want to discuss the topic further, please leave a comment below.