Question

I'm attempting to convert ch object array to double array
public void calculateSalesPrice() {
    double salePrice[] = new double[ch.length];
    int p = 0;
    for (int i = 0; i < ch.length; i += 3) {
        p = i + 1;
        for(int j = 0;j
    }
}

error message:items.java:16: error: cannot find symbol
for(int j = 0;j ^
symbol: variable length
location: class Object
items.java:17: error: array required, but Object found
salePrice[j] = (double

full program

import java.io.File;
import java.util.Scanner;
import java.util.ArrayList;
import javax.swing.JOptionPane;
import java.util.Arrays;
public class shoppingCart {
private ArrayList<String>listOfItems;
private String userInput;
private int itemCount;
private int selection_index;
public Object ch[];
public Object shopList, shopPrice;
private int itemsNum;
public int c;
public void shopperName(){
userInput=JOptionPane.showInputDialog(null, "Hello valued customer, please enter your name to continue.");
String userName= userInput;
int dialogButton= JOptionPane.showConfirmDialog ( null,"Welcome "+userInput+". Are you ready to shop?" );
if(dialogButton==JOptionPane.YES_OPTION){
JOptionPane.showMessageDialog(null, "Okay, Let's shop");
}
  
if(dialogButton== JOptionPane.NO_OPTION ){
JOptionPane.showMessageDialog(null, "Have a great day.");
System.exit(0);   
}
}
public void ListOfItemsAvailable(){
listOfItems= new ArrayList<String>(10);

Scanner itemList = null;
try {
itemList= new Scanner(new File ("list_Of_items.txt"));
while( itemList.hasNext()){
listOfItems.add(itemList.nextLine());
itemCount++;
}
}
catch (Exception ex) {
JOptionPane.showMessageDialog(null, "Error reading available items");
System.exit(1);
}
itemList.close();
}
public void printAvailableItems(){
System.out.println("Enter number in parenthesis to select item");
  
ch=listOfItems.toArray();
int i=0;int j=0;
for(i=0;i<ch.length;i+=3){
j=i+1;
System.out.println(ch[i]+" $" + ch[j] + " ("+ i+ ")");
shopList=ch[i];
shopPrice=ch[j];}

}
public void customerSelection(){// allow customer to make selection
System.out.println(" How many items do you want to buy");
Scanner scan= new Scanner(System.in);
itemsNum=scan.nextInt();
String[] itemsL= new String[itemsNum];

for(int k=0; k<itemsNum; k++){
System.out.println("Enter the number assigned to item: " + (k+1));
itemsL[k]=scan.next();}
scan.close();
for(int k=0; k<itemsNum; k++){
c=Integer.parseInt(itemsL[k]);
System.out.println("The items you selected are: " + ch[c]);
}
}
public void cart(){
Object Kart=ch[c];

}

public static void main( String args[]){
shoppingCart shopper = new shoppingCart();
shopper.shopperName();
shopper.ListOfItemsAvailable();// access list of available items from txt file
shopper.printAvailableItems();// print available items
shopper.cart();// holds the items in customers cart
shopper.customerSelection();// allow customer to select items
items register = new items();
register.calculateSalesPrice();// calculate sales price
register.payment();// accept customer payment

} }

import java.io.File;
import java.util.Scanner;
public class items extends shoppingCart{
private Object discount;
String itemName; double itemPrice; String ItemOnsale;
public items(){
}
public void calculateSalesPrice(){
double salePrice[]= new double[ch.length];
  
int p=0; int d=0;
for(int i=0;i<ch.length;i+=3){
p=i+1;
d=i+2;   
discount=ch[d];}
for(int j = 0;j<ch[p].length;j++){
salePrice[j] = (double) ch[p][j];   
}
}
public void payment(){
}    
}
txt file:

popcorn
3.50
yes
chips
2.00
no
corn curls
1.10
no

Answer 1

You can do this by having another loop variable j and increment it by 1 on each loop. Since price is at i+1 location, we can fill salePrice[] array as below:

for (int i = 0, j = 0; i < ch.length; i += 3, j++) {
            p = i + 1;
            d = i + 2;
            discount = ch[d];

            salePrice[j] = (double) ch[p]; // since price is at location p
}

In your code, you are trying to access 2d array ch which does not exist as ch is the single dimension array.

salePrice[j] = (double) ch[p][j];    // wrong

This completes the requirement. Let me know if you have any queries.

Thanks!