Merge branch 'go-basics-inventory' of https://gitty.informatik.th-mannheim.de/steger/pr3-code

go/01-basics/inventory.go

@@ -1,40 +1,107 @@
 package main
 
+import "fmt"
+
+// a new type named Category that can hold integer values
+type Category int
+
+// The go equivalent of an enum that enumerates different named Categories
+const (
+	Electronics Category = iota //0
+	Groceries                   //1
+	Clothes                     //2
+)
+
+// implementation of the fmt.Stringer interface. In that way, Categories can be printed using the fmt.Print* functions
+func (c Category) String() string {
+	switch c {
+	case Electronics:
+		return "Electronics"
+	case Groceries:
+		return "Groceries"
+	case Clothes:
+		return "Clothes"
+	default:
+		return "Unknown"
+	}
+}
+
+// Struct for product details
 type Product struct {
 	Name     string
 	Price    float64
 	Quantity int
-	Category string //TODO: use enum instead
+	Category Category
 }
 
-func addProduct(inventory *[]Product, name string, price float64, quantity int, category string) {
-	//TODO: implement
+// Add a new product to the inventory
+func addProduct(inventory *[]Product, //pointer to the slice of of Products that shall be modified. In that way it can serve as in input/output parameter
+	name string, price float64, quantity int, category Category) {
+	// Check if the product already exists in the inventory
+	for _, product := range *inventory {
+		if product.Name == name {
+			fmt.Println("Product already exists.")
+			return
+		}
+	}
+	// Add the new product
+	*inventory = append(*inventory, Product{
+		Name:     name,
+		Price:    price,
+		Quantity: quantity,
+		Category: category,
+	})
+	fmt.Printf("Added product: %s\n", name)
 }
 
-func removeProduct(inventory *[]Product, name string) {
-	//TODO: implement
+// Remove a product from the inventory
+func removeProduct(inventory *[]Product, //pointer to the slice of of Products that shall be modified. In that way it can serve as in input/output parameter
+	name string) {
+	for i, product := range *inventory {
+		if product.Name == name {
+			*inventory = append((*inventory)[:i], (*inventory)[i+1:]...)
+			fmt.Printf("Removed product: %s\n", name)
+			return
+		}
+	}
+	fmt.Println("Product not found.")
 }
 
-func updateQuantity(inventory *[]Product, name string, newQuantity int) {
-	//TODO: implement
+// Update the quantity of a product.
+func updateQuantity(inventory *[]Product, //pointer to the slice of of Products that shall be modified. In that way it can serve as in input/output parameter
+	name string, newQuantity int) {
+	for i, product := range *inventory {
+		if product.Name == name {
+			(*inventory)[i].Quantity = newQuantity
+			fmt.Printf("Updated quantity for %s: New Quantity = %d\n", name, newQuantity)
+			return
+		}
+	}
+	fmt.Println("Product not found.")
 }
 
+// Display the inventory
 func displayInventory(inventory []Product) {
-	//TODO: implement
+	fmt.Println("Inventory:")
+	for _, product := range inventory { //iterating over a range returns pairs of index and the content of a container (here: inventory). Since we don't care about the index, we use _ as a placeholder.
+		fmt.Printf("%s - %s (Price: $%.2f, Quantity: %d)\n",
+			product.Name, product.Category, product.Price, product.Quantity)
+	}
 }
 
 func main() {
+	// Initialize inventory
 	inventory := []Product{
-		{Name: "Laptop", Price: 1000, Quantity: 5, Category: "Electronics"},
-		{Name: "Apples", Price: 2, Quantity: 50, Category: "Groceries"},
-		{Name: "T-shirt", Price: 10, Quantity: 20, Category: "Clothes"},
+		{Name: "Laptop", Price: 1000, Quantity: 5, Category: Electronics},
+		{Name: "Apples", Price: 2, Quantity: 50, Category: Groceries},
+		{Name: "T-shirt", Price: 10, Quantity: 20, Category: Clothes},
 	}
 
 	// Display initial inventory
 	displayInventory(inventory)
 
 	// Add a new product
-	addProduct(&inventory, "Phone", 800, 10, "Electronics")
+	addProduct(&inventory, "Phone", 800, 10, Electronics)
 
 	// Display updated inventory
 	displayInventory(inventory)