Date: 06/24/06 (Algorithms)    Keywords: web

Here is some code from a uc berkeley lecture on insertion sort (available from the amazing berkeley webcasts, CS61B, "Sorting I" lecture ):
Presumably A is an existing array.

for (int i=1; i   int j;
   Object x = A[i];
   for (j=i-1; j>= 0; j-= 1) {
      if (A[j].compareTo (x) <= 0)  /* (1) */
         break;
      A[j+1] = A[j];
   }
   A[j+1] = x;
}


I have two questions (I'm not in the class, just watching the webcasts):
1)  In the code "A[j].compareTo(x)", I imagine that compareTo is some kind of callback which is supposed to already be implemented on this type of data. Is there a way I'm supposed to know how the callback is supposed to behave - I figure it returns 0 when the values are equal, but what about if a is greater than b? By the logic of this program, a.compareTo(b) returns something less than 0 if a is less than b. Is this behavior standard, or just a function of this program?

2) There is a comment that says "/*  (1)   */"
I don't understand what this means. Does anyone else?

Thanks.

Source: http://community.livejournal.com/algorithms/79867.html