Thread: Sorting Array & Binary Search Help

I am trying to sort my array of DVDs without using a sorting algorithm. This works with 4 or so DVDs but displays error java.lang.ArrayIndexOutOfBoundsException: 4 with anymore added.

I don't know why it is doing this.

My other problem is implementing a binary search.

import java.text.NumberFormat;
 
 
public class DVD 
{
   public String title, director;
   private int year;
   private double cost;
   private boolean bluRay;
 
 
 
   public DVD (String title, String director, int year, double cost,
      boolean bluRay)
   {
      this.title = title;
      this.director = director;
      this.year = year;
      this.cost = cost;
      this.bluRay = bluRay;
   }
 
   public String getTitle(){
       return title;
    }
 
 
 
 
   public String toString()
   {
      NumberFormat fmt = NumberFormat.getCurrencyInstance();
 
      String description;
 
      description = fmt.format(cost) + "\t" + year + "\t";
      description += title + "\t" + director;
 
      if (bluRay)
         description += "\t" + "Blu-Ray";
 
      return description;
   }
}

import java.text.NumberFormat;
 
 
public class DVDCollection 
{
   private DVD[] collection;
   private int count;
   private double totalCost;
   private double average;
 
   public DVDCollection ()
   {
      collection = new DVD[0];
      count = 0;
      totalCost = 0.0;
 
    }
 
 
   public void addDVD (String title, String director, int year, double cost, boolean blueray)
   {
 
         DVD[] temp = new DVD[collection.length + 1];
         int index = 0;
         int i = 0;
         for(;  0 < collection.length; i++) 
              {
             if(collection[i].getTitle().compareTo(title)>0) {
                 temp[index++] = new DVD (title, director, year, cost, blueray);
                 break;
                }
 
              temp[index++] = collection[i];
 
           }
 
            for(; i < collection.length; i++){
                  temp[index++] = collection[i];
                 }
       if(index != temp.length)
             temp[index] = new DVD (title, director, year, cost, blueray);
 
         collection = temp;
       totalCost += cost;
      average=totalCost/collection.length;
    }
 
   public String toString()
   {
      NumberFormat fmt = NumberFormat.getCurrencyInstance();
 
      String report = "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n";
      report += "My DVD Collection\n\n";
 
      report += "Number of DVDs: " + collection.length + "\n";
      report += "Total cost: " + fmt.format(totalCost) + "\n";
      report += "Average cost: " + average;
 
      report += "\n\nDVD List:\n\n";
 
      for (int i = 0; i < collection.length; i++)
         report += collection[i] + "\n";
 
      return report;
   }
 
 
   private void increaseSize ()
   {
      DVD[] temp = new DVD[collection.length * 2];
 
      for (int dvd = 0; dvd < collection.length; dvd++)
         temp[dvd] = collection[dvd];
 
      collection = temp;
   }
}

 
public class Movies
{
   //-----------------------------------------------------------------
   //  Creates a DVDCollection object and adds some DVDs to it. Prints
   //  reports on the status of the collection.
   //-----------------------------------------------------------------
   public static void main (String[] args)
   {
      DVDCollection movies = new DVDCollection();
 
      movies.addDVD ("The Godfather", "Francis Ford Coppala", 1972, 24.95, true);
      movies.addDVD ("District 9", "Neill Blomkamp", 2009, 19.95, false);
      movies.addDVD ("Iron Man", "Jon Favreau", 2008, 15.95, false);
      movies.addDVD ("All About Eve", "Joseph Mankiewicz", 1950, 17.50, false);
      movies.addDVD ("The Matrix", "Andy & Lana Wachowski", 1999, 19.95, true);
 
      System.out.println (movies);
 
      movies.addDVD ("Iron Man 2", "Jon Favreau", 2010, 22.99, false);
      movies.addDVD ("Casablanca", "Michael Curtiz", 1942, 19.95, false);
 
      System.out.println (movies);
   }
}

public static Comparable searchForDVD (Comparable[] collection, Comparable target)
   {
      int min=0, max=collection.length-1, mid=0;
      boolean found = false;
 
      while (!found && min <= max)
      {
          mid = (min+max) / 2;
          if (collection[mid].compareTo(target) == 0)
            found = true;
          else
          if (target.compareTo(collection[mid]) < 0)
            max = mid-1;
          else
            min = mid+1;
       }
          if (found)
            return collection[mid];
          else
            return -1;
   }

I see what you're saying...how can I sort it without sorting...if I swap values it is sorting...

Originally Posted by xJavaLover

I see what you're saying...how can I sort it without sorting...if I swap values it is sorting...

Anyone wanna help me figure out how to sort this array of collection objects?

I am trying to sort it using a loop. I currently recieve a null exception.

public void addDVD (String title, String director, int year,
      double cost, boolean bluRay)
   {
       if (count == collection.length)
            increaseSize();
 
       DVD[] temp = new DVD[collection.length];
       for (int i = 0; i < collection.length - 1; i++)
       {
           for (int j = i; j < collection.length; j++)
           {
               if (collection[i].getTitle().compareTo(collection[j].getTitle())>0)
                temp[i] = new DVD(title, director, year, cost, bluRay);
                temp[i] = collection[i];
                collection[i] = collection[j];
                collection[j] = temp[i];
           }
       }   
 
       collection[count] = new DVD (title, director, year, cost, bluRay);
       totalCost += cost;
       count++;
   }

if (collection[i].getTitle().compareTo(collection[j].getTitle())>0)

is where the null error is occuring.