/**
 * A demo of selection sort.
 * @author Sean Barker
 */
public class SelectionSort {

    private static void swap(int[] data, int i, int j) {
        int temp = data[i];
        data[i] = data[j];
        data[j] = temp;
    }

    public static void selectionSort(int[] data) {
        for (int unsorted = data.length; unsorted > 0; unsorted--) {
            
            int largest = 0; // index of largest value this pass
            for (int i = 1; i < unsorted; i++) {
                if (data[largest] < data[i]) {
                    largest = i; // found a new index of largest value
                }
            }
            swap(data, largest, unsorted - 1); // put the largest value into position
            
        }
    }

    public static void main(String[] args) {
        selectionSortDemo(10, 100);
    }
    
    /**
     * Runs a demo of selection sort (same algorithm as above, but uses the SortSim
     * class to display the steps of the sort).
     */
    public static void selectionSortDemo(int dataSize, int maxVal) {
        SortSim s = new SortSim(dataSize, maxVal);
        int[] data = s.getData();

        s.update(false, -1, -1, "starting selection sort");
        for (int unsorted = data.length; unsorted > 0; unsorted--) {
            int largest = 0; // index of largest value this pass
            for (int i = 1; i < unsorted; i++) {
                if (data[largest] < data[i]) {
                    largest = i;
                }
                s.update(false, largest, i, "best candidate is " + data[largest]);
            }
            swap(data, largest, unsorted - 1);
            s.update(true, largest, unsorted - 1, "sorted next-largest value " + data[unsorted - 1]);
        }
        s.finish();
    }

}