Going back to Java after so many years is an interesting experience. I made the classic rookie mistake with implementation of a sorting library. All good programming practices tell you that manipulation methods on a collection should always be static and not bound to the class. To top it all, this was the first time I was using generics after spending some time reading about them :)
I had done things the other way around, almost as if I had implemented a stack with data. My ego was too big for me not to succeed with that technique. Here is an implementation of selection sort. Below is what I ended up implementing
I had done things the other way around, almost as if I had implemented a stack with data. My ego was too big for me not to succeed with that technique. Here is an implementation of selection sort. Below is what I ended up implementing
/** * * @author balbir * @param- */ public class SelectionSort < Item extends Comparable >
- { private Item[] elements; SelectionSort(int N) { elements = (Item[]) new Comparable[N]; } public void sort() { int min; for (int i = 0; i < elements.length; i++) { min = i; for (int j = i+1; j < elements.length; j++) { if (elements[j].compareTo(elements[min]) < 0) min = j; } Item tmp; tmp = elements[i]; elements[i] = elements[min]; elements[min] = tmp; } } public void dump() { for (int i = 0; i < elements.length; i++) System.out.print(elements[i] + " "); System.out.println(); } public void load(Item a[]) { for (int i = 0; i < elements.length; i++) elements[i] = a[i]; } /** * @param args the command line arguments */ public static void main(String[] args) { // TODO code application logic here Integer[] a = {1, 2, -1, 3, 0, 5, 7, 9, 4}; SelectionSort
s = new SelectionSort (a.length); s.load(a); s.dump(); s.sort(); s.dump(); } }
It is funny how I had to use a load class to get the data and call the sort method. What a bad decision, the reason I shared this post is just to show that with generics one can indeed mix classes and class templates. I for example mixed Integer and Comparable and the default implementation worked.
