Reverse sort of array

[E Ni]

Is there anyway to sort an array in reverse order?
I tried using Arrays.sort() but this sorts in ascending order but can you do this for descending order?

[Nathaniel Stoddard]

It looks like it depends on what is in the array. If the elements of the array are primitives, then you're stuck. However, if they are Objects, then you can use sort(array, comparator), where comparator is an object that implements the Comparator interface, sorting it in whatever order you want.
(This is all in the API docs for java.util.Arrays).

[E Ni]

Its an array of integers. Is there any way I can sort this?

[Michael Dunn]

Here's a round-about way of doing it

import java.util.*;
class SortArrayInReverse
{
  public SortArrayInReverse()
  {
    int[] numbers = {10,1,25,65,24,82,3};
    ArrayList list = new ArrayList();
    for(int x = 0; x < numbers.length; x++) list.add(new Integer(numbers[x]));
    Comparator comp = new ReverseSorter();
    Collections.sort(list,comp);
    for(int x = 0; x < numbers.length; x++)
    {
      numbers[x] = Integer.parseInt(list.get(x).toString());
      System.out.println(numbers[x]); 
    }    
    System.exit(0);
  }
  public static void main(String[] args) {new SortArrayInReverse();}
}
class ReverseSorter implements Comparator
{
  public int compare(Object o1, Object o2)
  { 
    return (new Integer(o1.toString()).compareTo(new Integer(o2.toString()))) * -1;
  }
}

[Blake Minghelli]

Here's another possibility...

import java.util.*;
public class DescSort {
public static void main (String args[]) {
int numbers[] = {12, 15, 1, 3, 9, 7, 54, 20};
// Start by sorting it in asc order
Arrays.sort(numbers);
// If you don't need them actually stored in desc order
// then you can just access them in desc order
for (int i = (numbers.length - 1); i >= 0; i--) {
System.out.print(numbers[i] + ", ");
}
System.out.println();
// OR, If they must be stored in the desc order,
// then you could create a new array
int descNumbers[] = new int[numbers.length];
int x = 0;
for (int i = (numbers.length - 1); i >= 0; i--) {
descNumbers[x] = numbers[i];
x++;
}
for (int i = 0; i < descNumbers.length; i++) {
System.out.print(descNumbers[i] + ", ");
}
System.out.println();
}
}  

[Wayne L Johnson]

Or you could sort them (in ascending order) and then call the "Collections.reverse()" method to reverse them.
[ADDED]This would require converting the Array to ArrayList, do the sort and "reverse()", and then convert it back to an Array.
[ March 10, 2004: Message edited by: Wayne L Johnson ]