Need Some Help When I Run The Program I Get This Error Message Exception in thre

Question

Need Some Help When I Run The Program I Get This Error Message

Exception in thread "main" java.util.InputMismatchException
at java.util.Scanner.throwFor(Scanner.java:864)
at java.util.Scanner.next(Scanner.java:1485)
at java.util.Scanner.nextDouble(Scanner.java:2413)
at Driver.main(Driver.java:101)

//Driver.java
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.Scanner;
public class Driver
{
   public static void main(String[] args)
   {
   String fileName = "items.txt";
   Scanner scanner = null;
   ItemsList itemsList = new ItemsList(5);
   int i = 0;

   try
   {
   scanner = new Scanner(new File(fileName));

   while(scanner.hasNextLine())
   {
   String itemName = scanner.next();
   double price = scanner.nextDouble();
   int qty = scanner.nextInt();

   //Add the OneItem object to the itemList
   itemsList.addItem(new OneItem(itemName, price, qty));
   i++;
   }

   //close the file objct
   scanner.close();

   //print the list of the items in itemsList
   System.out.println(itemsList.toString());
   }
   catch (FileNotFoundException e)
   {
   System.out.println(e.getMessage());
   }

   boolean repeat=true;
   //Create an instance of Scanner class
   scanner = new Scanner(System.in);

   while(repeat)
   {
   int choice = menu();

   switch (choice)
   {
   //Add an item to the itemsList
   case 1:
System.out.println("Enter item name : ");
   String name = scanner.nextLine();
  
   System.out.println("Enter price : ");
   double price = Double.parseDouble(scanner.nextLine());
  
   System.out.println("Enter quantity : ");
   int quantity = Integer.parseInt(scanner.nextLine());

   //Add the OneItem to the itemsList
   itemsList.addItem(new OneItem(name, price, quantity));

break;

   case 2:
   //print the list
   System.out.println(itemsList.toString());
   break;
   case 3:
   //Terminate the program
   System.out.println("Exit the program.");
   //set repeat to false
   repeat=false;
   break;
   default:
   System.out.println("Error!! Try Again");
   break;
   }
   }
   writeToFile(itemsList);
   }
  
   private static void writeToFile(ItemsList itemsList)
   {
   //Create a file name called items.txt
   String filename = "items.txt";
  
   //Create a variable of Class PrintWriter
   PrintWriter filewriter = null;

   try
   {
   //create an instance of PrintWriter
   filewriter = new PrintWriter(new File(filename));
   filewriter.println(itemsList.toString());
  
   //close the filewriter
   filewriter.close();
   }
   catch (IOException e)
   {
   System.out.println(e.getMessage());
   }
   }
  
   //Method : Menu
   private static int menu()
   {
   //Create an instance of Scanner class
   Scanner keyboard=new Scanner(System.in);
   System.out.println(" Menu ");
   System.out.println(" 1. Add item");
   System.out.println(" 2. Display items");
   System.out.println(" 3. Exit");
   System.out.println(" Enter your choice");
   int choice=Integer.parseInt(keyboard.nextLine());
   return choice;

   }
}//end Driver class

---------------------------

public class ItemsList
{
   //declare variables
   private OneItem items[];
   private int size;
   private int count;

   //constructor to set items, size and count to zero
   public ItemsList()
   {
   items = null;
   size = 0;
   count = 0;
   }
   //Parameter constructor
   public ItemsList(int size)
   {
   items = new OneItem[size];

   for (int i = 0; i < items.length; i++)
   {
   items[i] = new OneItem();
   }

   this.size = size;
   count = 0;
   }
   //Add OneItem to the itemlist
   public void addItem(OneItem item)
   {
   if(items.length == count)
   {
   resize();
   items[count] = item;
   count++;
   }
   else
   {
   items[count] = item;
   count++;
   }
   }
  
   //Resize
   private void resize()
   {
   int oldsize = size;
   count = oldsize;
   int newsize = 2 * this.size;
   size = newsize;
  
   OneItem[] tempList = new OneItem[size];

   for (int i = 0; i < oldsize; i++)
tempList[i] = items[i];


   items = new OneItem[size];
   items = tempList;
   }

   //getSize
   public int getSize()
   {
   return count;
   }

   //toString
   public String toString()
   {
   String description = "";

   description += String.format("%-10s%-10s%-10s ", "Item","Price","Quantity");

   for (int i = 0; i <count; i++)
   {
   description += items[i].toString();
   }

   return description;
   }
}

-------------------------------------------

//OneItem.java
public class OneItem
{
   //declare a variables
   private String name;
   private double price;
   private int quantity;
   //default constructor
   public OneItem()
   {
   name="";
   price=0;
   quantity=0;
   }
   //parameter constructor
   public OneItem(String name, double price, int quantity)
   {
   this.name=name;
   this.price=price;
   this.quantity=quantity;
   }

   //Override the toString
   @Override
   public String toString() {
   return String.format("%-10s%-10.2f%-10d ", name,price,quantity);
   }
}//end of the OneItem class

Include the following in your program: 1. Create a Class representing the information that is associated with one item of your database. The information for one item must include a minimum of 3 fields. Within the Class for one item, include the following methods: 1. A constructor that accepts the information about one item and assigns it to the instance data within this Class. 2. A method that prints the information about one item of your collection. Name this method toString NOTE: It is important that you name this method toString because it's one of Java's built-in methods that allows you print out your Object. 2. Create another Class with an array of Objects of the Class of one item with the following methods: 1. Create an array of the Objects from the Class of one item 2. Create a constructor to initialize the number of items in the array to zero. 3. Create a method to add one item at a time to the array. 4. Create a method to display the contents of the entire array. Call this method toString. 5. Create a method to increase the size of the array if it is getting full 3. Create a Driver Class with a Menu with the option to add an item, to print out a list of all items, and exit. 4. When your program is first executed, read the data from an external file and place it in your array. Submit the external file with program o To populate the external file for the first time, hard code into your program sending data to the external file. You will only need to do this once - just when you've created the external file for the first. 5. Save the data back to the external file when the Exit option is chosen from the menu in the Drive. NOTE: You MUST read your data from an external file! You MUST save your data back to that external file when done

Explanation / Answer

InputMismatchException: Thrown by a Scanner to indicate that the token retrieved does not match the pattern for the expected type, or that the token is out of range for the expected type.

You need to check the content of "items.txt". They should comply with "String Double Int". e.g. Sam 12.2 90

I think you want to do this on your own. If you need full code let me know in comments.

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