Sorting

[jibs parap]

  import static java.lang.System.out;
import java.util.*;
class Stepper {
 
  public static void main(String... bang) {
 
  String[] words = {"Good", "Bad", "Ugly"};
  Comparator<String> best = new Comparator<String>(){
  public int compare(String s1, String s2){
  return s2.charAt(1)-s1.charAt(1);
  }
  };
 
  Arrays.sort(words, best);
  out.println(words[0]);
 
  }
}  

Can anyone explain the logic of sorting here by using s2.charAt(1)-s1.charAt(1) as coded above please. Thanks in advance.

[marc weber]

By adding some println statements, the code will explain itself...

import static java.lang.System.out;
import java.util.*;
 
class Stepper {
  public static void main(String... bang) {
    String[] words = {"Good", "Bad", "Ugly"};
    Comparator<String> best = new Comparator<String>() {
      public int compare(String s1, String s2) {
        out.println("\nComparing " + s1 + " & " + s2);
 
        //these are the chars we're comparing...
        char s1charAt1 = s1.charAt(1);
        char s2charAt1 = s2.charAt(1);
 
        //these chars have the following int values...
        int s1charAsInt = (int)s1charAt1;
        int s2charAsInt = (int)s2charAt1;
 
        //output the chars and their values...
        out.println(" chars: " + s2charAt1 + " & " + s1charAt1);
        out.println(" ints: " + s2charAsInt + " & " + s1charAsInt);
 
        //here's what we're returning...
        out.println(" Do the math: " + s2charAsInt + " - " + s1charAsInt);
        return s2.charAt(1)-s1.charAt(1);
      }
    };
 
    Arrays.sort(words, best);
    out.println("\nFinal output (words[0]): " + words[0]);
  }
}

[ July 29, 2007: Message edited by: marc weber ]

[Noam Wolf]

So it seems the logic is to compare the first letter of the compared strings and return a positive number if the s2 starts with a "higher" (in the alphabet) letter, a negative number if s1 starts with a "higher" letter, and 0 if they are they same.... right?

[Remko Strating]

That's not true.

s1.charAt(1) retrieves the second char, because this method is zero based.

[jibs parap]

Thanks Remco. That was interesting to see.
But hows the array sorted based on the return value. The final array is {Good, Ugly, Bad} after sorting.

[jibs parap]

Sorry, I was a bit drowsy, when sorted it last.
Now sorted perfect.

Cheers guys