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Thread: BlueJ trouble or program trouble (Combining Arraylists)

  1. #1
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    Default BlueJ trouble or program trouble (Combining Arraylists)

    I'm doing is on BlueJ and it won't work. I've waited for 15 min. It compiles and there's no error when I hit main(), but it just keeps loading. Is it my code (does it have a super slow runtime?). If it is my code, I think that it is the way I combined the two Arraylists. Is there a better way to combine the lists is ascending order?

    import java.util.Scanner;
    import java.io.*; 
    import java.util.ArrayList;
    public class MergeInventoriesTester
    {
       private ArrayList<Product> Store1;
       private ArrayList<Product> Store2;
     
     
       private Product store1;
       private static Product store2;
       public static void main() throws FileNotFoundException
       {
           ArrayList<Product> Store1 = new ArrayList<Product>();
           ArrayList<Product> Store2 = new ArrayList<Product>();
     
           getTextFile(Store1, Store2);
           mergeArrayLists(Store1, Store2);
       }
       public static void getTextFile(ArrayList<Product> Store1, ArrayList<Product> Store2)throws FileNotFoundException
       {
           String id;
           String quantity;
           String unitPerPrice;
           Scanner inF = new Scanner(new File("C:\\Users\\Caili\\Documents\\Sophmore\\AP Computer Science\\Chapter 14\\Store1.txt"));
     
           while(inF.hasNextLine())
           {
               id = inF.nextLine();
               quantity = inF.nextLine();
               unitPerPrice = inF.nextLine();
               Store1.add(new Product(id, quantity, unitPerPrice));
           }
     
           Scanner inE = new Scanner(new File("C:\\Users\\Caili\\Documents\\Sophmore\\AP Computer Science\\Chapter 14\\Store2.txt"));
           while(inE.hasNextLine())
           {
               id = inE.nextLine();
               quantity = inE.nextLine();
               unitPerPrice = inE.nextLine();
               Store2.add(new Product(id, quantity, unitPerPrice));
           }
     
     
       }
       public static void mergeArrayLists(ArrayList<Product> Store1, ArrayList<Product> Store2) throws FileNotFoundException
       {
           ArrayList<Product> Merged = new ArrayList<Product>();
           int a = 0;;
           int b = 0;
           while(a < Store1.size()&& b < Store2.size())
           {
                if(Store1.get(a).returnID().compareTo(Store2.get(B).returnID())==1)
                {
                     Merged.add(Store1.get(a));
                     a++;
                }
     
                if(Store1.get(a).returnID().compareTo(Store2.get(B).returnID())==-1)
                {
                     Merged.add(Store2.get(B));
                     b++;
                }
     
                if(Store1.get(a).returnID().compareTo(Store2.get(B).returnID())==0)
                {
                    Merged.add(Store1.get(a));
                    a++;
                    b++;
                }
     
           }
           for(int i=0; i<Merged.size();i++)
            {
                Product person = Merged.get(i);
                System.out.println(person.returnID());
            }
     
       }
    }
    public class Product
    {
       private String id;
       private double quantity;
       private double unitPerPrice;
       private double value;
       public Product(String num,String amount,String perPrice)
       {
           id = num;
           quantity = Double.parseDouble(amount);
           unitPerPrice = Double.parseDouble(perPrice);
       }
       public String returnID()
       {
           return id;
       }
    }


  2. #2
    Super Moderator Norm's Avatar
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    Default Re: BlueJ trouble or program trouble (Combining Arraylists)

    it just keeps loading
    Do you mean the program goes into a loop and stops responding?
    Otherwise please explain what "keeps loading" means.

    Add some println statements that will show where the program is executing.

  3. #3
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    Default Re: BlueJ trouble or program trouble (Combining Arraylists)

    If you wanna merge 2 lists, why dont you just use:
    Collections.copy(destinationList, sourceList);

  4. #4
    Super Moderator Norm's Avatar
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    Default Re: BlueJ trouble or program trouble (Combining Arraylists)

    Does the copy method merge or overlay the destination list?

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