comments for inventory

go/01-basics/inventory.go

@@ -2,14 +2,17 @@ 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
-	Groceries
-	Clothes
+	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:
@@ -32,7 +35,8 @@ type Product struct {
 }
 
 // Add a new product to the inventory
-func addProduct(inventory *[]Product, name string, price float64, quantity int, category Category) {
+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 {
@@ -51,7 +55,8 @@ func addProduct(inventory *[]Product, name string, price float64, quantity int,
 }
 
 // Remove a product from the inventory
-func removeProduct(inventory *[]Product, name string) {
+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:]...)
@@ -62,8 +67,9 @@ func removeProduct(inventory *[]Product, name string) {
 	fmt.Println("Product not found.")
 }
 
-// Update the quantity of a product
-func updateQuantity(inventory *[]Product, name string, newQuantity int) {
+// 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
@@ -77,7 +83,7 @@ func updateQuantity(inventory *[]Product, name string, newQuantity int) {
 // Display the inventory
 func displayInventory(inventory []Product) {
 	fmt.Println("Inventory:")
-	for _, product := range 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)
 	}