Untitled

def add_to_shopping_list(item, shopping_list, available_stock):
    if item in available_stock:
        shopping_list.append(item)
        return f"'{item}' added to your shopping list."
    else:
        return f"Error: '{item}' is not available in stock."

def check_items_in_stock(shopping_list, available_stock):
    shopping_set = set(shopping_list)
    unavailable_items = shopping_set - available_stock
    if unavailable_items:
        return f"The following items are not available: {', '.join(unavailable_items)}"
    else:
        return "All items in your shopping list are available!"

# Main program
def main():
    # Available stock (set)
    available_stock = {"apples", "bananas", "carrots", "milk", "bread", "eggs"}
    
    # Shopping list (list)
    shopping_list = []

    print("Welcome to the Grocery Shopping System!")
    print(f"Available stock: {', '.join(available_stock)}\n")

    while True:
        print("\nOptions:")
        print("1. Add an item to the shopping list")
        print("2. Check if items in your shopping list are in stock")
        print("3. View your shopping list")
        print("4. Exit")

        try:
            choice = int(input("Enter your choice (1-4): "))

            if choice == 1:
                item = input("Enter the item you want to add: ").lower()
                result = add_to_shopping_list(item, shopping_list, available_stock)
                print(result)
            elif choice == 2:
                result = check_items_in_stock(shopping_list, available_stock)
                print(result)
            elif choice == 3:
                print(f"Your shopping list: {', '.join(shopping_list) if shopping_list else 'No items yet.'}")
            elif choice == 4:
                print("Exiting the program. Happy shopping!")
                break
            else:
                print("Invalid choice. Please enter a number between 1 and 4.")
        except ValueError:
            print("Error: Please enter a valid number!")

# Run the main program
if __name__ == "__main__":
    main()