Question

Need help debugging.

Create an application that keeps track of the items that a wizard can carry.

console application which has no errors:

import java.util.Scanner;

public class Console {
  
    private static Scanner sc = new Scanner(System.in);

    public static String getString(String prompt) {
        System.out.print(prompt);
        String s = sc.nextLine();
        return s;
    }

    public static int getInt(String prompt) {
        int i = 0;
        boolean isValid = false;
        while (!isValid) {
            System.out.print(prompt);
            if (sc.hasNextInt()) {
                i = sc.nextInt();
                isValid = true;
            } else {
                System.out.println("Error! Invalid integer. Try again.");
            }
            sc.nextLine(); // discard any other data entered on the line
        }
        return i;
    }

    public static int getInt(String prompt, int min, int max) {
        int i = 0;
        boolean isValid = false;
        while (!isValid) {
            i = getInt(prompt);
            if (i <= min) {
                System.out.println(
                        "Error! Number must be greater than " + min + ".");
            } else if (i >= max) {
                System.out.println(
                        "Error! Number must be less than " + max + ".");
            } else {
                isValid = true;
            }
        }
        return i;
    }

    public static double getDouble(String prompt) {
        double d = 0;
        boolean isValid = false;
        while (!isValid) {
            System.out.print(prompt);
            if (sc.hasNextDouble()) {
                d = sc.nextDouble();
                isValid = true;
            } else {
                System.out.println("Error! Invalid number. Try again.");
            }
            sc.nextLine(); // discard any other data entered on the line
        }
        return d;
    }

    public static double getDouble(String prompt, double min, double max) {
        double d = 0;
        boolean isValid = false;
        while (!isValid) {
            d = getDouble(prompt);
            if (d <= min) {
                System.out.println(
                        "Error! Number must be greater than " + min + ".");
            } else if (d >= max) {
                System.out.println(
                        "Error! Number must be less than " + max + ".");
            } else {
                isValid = true;
            }
        }
        return d;
    }
}

//-------------------------------------------------------------------------------------------------------------------------

WizardInventoryApp class which has several errors:

import java.util.ArrayList;
import java.util.List;

public class WizardInventoryApp {

    public static void main(String[] args) {
        System.out.println("The Wizard Inventory application\n");
      
        displayMenu();

        // all players start with these 3 items
        ArrayList inventory = new ArrayList<>();
        inventory("wooden staff");
        inventory("wizard hat");
        inventory("cloth shoes");

        String command = Console.getString("Command: ");
        while (command.equals("exit") {      
          
            if (command.equals("show")) {
                show(inventory);
            } else if (command.equals("grab")) {
                grabItem(inventory);
            } else if (command.equals("edit")) {
                editItem(inventory);
            } else {
                System.out.println("Not a valid command. Please try again.\n");
            }
        }
        System.out.println("Bye!");
    }
  
    private static void displayMenu() {
        System.out.println("COMMAND MENU");
        System.out.println("show - Show all items");
        System.out.println("grab - Grab an item");
        System.out.println("edit - Edit an item");
        System.out.println("exit - Exit program");
        System.out.println();
    }

    private static void show(List inventory) {
        for (int i = 0; i < inventory; i++) {
            String item = inventory(i);
            int number = i + 1;
            System.out.println(number + ". " + item);
        }
        System.out.println();
    }

    private static void grabItem(List inventory) {
        if (inventory >= 4) {
            System.out.println("You can't carry any more items. " +
                  "Drop something first.\n");
        } else {
            String item = Console.getString("Name: ");
            inventory(item);
            System.out.println(item + " was added.\n");
        }
    }

    private static void editItem(List inventory) {
        int number = Console.getInt("Number: ");
        if (number < 1 || number > inventory {
            System.out.println("Invalid item number.\n");
        } else {
            String item = Console.getString("Updated name: ");
            inventory(number-1, item);
            System.out.println("Item number " + number + " was updated.\n");
        }
    }

    private static void dropItem(List inventory) {
        int number = Console.getInt("Number: ");
        if (number < 1 || number > inventory {
            System.out.println("Invalid item number.\n");
        } else {
            String item = inventory(number-1);
            System.out.println(item + " was dropped.\n");
        }
    }
}

Answer 1

import java.util.ArrayList;
import java.util.List;

public class WizardInventoryApp {

    public static void main(String[] args) {
        System.out.println("The Wizard Inventory application\n");

        displayMenu();

        // all players start with these 3 items
        ArrayList inventory = new ArrayList<>();//specify type
        inventory.add("wooden staff");//use add method to insert into array list
        inventory.add("wizard hat");
        inventory.add("cloth shoes");

        String command = Console.getString("Command: ");
        while (!command.equals("exit")) {//it should be while command not equals to exit

            if (command.equals("show")) {
                show(inventory);
            } else if (command.equals("grab")) {
                grabItem(inventory);
            } else if (command.equals("edit")) {
                editItem(inventory);
            } else if (command.equals("drop")) {
                dropItem(inventory);
            } else {
                System.out.println("Not a valid command. Please try again.\n");
            }
            command = Console.getString("Command: ");//ask again
        }
        System.out.println("Bye!");
    }

    private static void displayMenu() {
        System.out.println("COMMAND MENU");
        System.out.println("show - Show all items");
        System.out.println("grab - Grab an item");
        System.out.println("edit - Edit an item");
        System.out.println("drop - Drop an item");
        System.out.println("exit - Exit program");
        System.out.println();
    }

    private static void show(List inventory) {
        for (int i = 0; i < inventory.size(); i++) {//use size to get length
            String item = (String) inventory.get(i);//cast to string
            int number = i + 1;
            System.out.println(number + ". " + item);
        }
        System.out.println();
    }

    private static void grabItem(List inventory) {
        if (inventory.size() >= 4) {//use size
            System.out.println("You can't carry any more items. " +
                    "Drop something first.\n");
        } else {
            String item = Console.getString("Name: ");
            inventory.add(item);//use add method
            System.out.println(item + " was added.\n");
        }
    }

    private static void editItem(List inventory) {
        int number = Console.getInt("Number: ");
        if (number < 1 || number > inventory.size()) {//use size
            System.out.println("Invalid item number.\n");
        } else {
            String item = Console.getString("Updated name: ");
            inventory.set(number - 1, item);//use set to update an index
            System.out.println("Item number " + number + " was updated.\n");
        }
    }

    private static void dropItem(List inventory) {
        int number = Console.getInt("Number: ");
        if (number < 1 || number > inventory.size()) {//use size
            System.out.println("Invalid item number.\n");
        } else {
            String item = (String) inventory.remove(number - 1);
            System.out.println(item + " was dropped.\n");
        }
    }
}