public class SelectionSort
{
/**
  Source: Savitch, Display 6.11
  Precondition: numberUsed <= a.length;
  The first numberUsed indexed variables have values.
  Action: Sorts a so that a[0] <= a[1] <= a[2] ... <= a[numberUsed-1];
 */

 public static void sort(double[] a, int numberUsed)
 {
 	int index, indexOfNextSmallest;
 	for (index=0; index < numberUsed - 1; index++)
 	{//Place the correct value in a[index];
 		indexOfNextSmallest = indexOfSmallest(index,a,numberUsed);
 		interchange(index,indexOfNextSmallest, a);
 		// a[0] <= a[1] ,,, < a[index] and these are the smallest
 		// of the original array elements.  The remaining positions
 		// contain the rest of the original array elements.
 	}
 }

 /** Returns the index of the smallest value among a[startIndex] ... a[numberUsed - 1]
 */
 private static int indexOfSmallest(int startIndex, double[] a, int numberUsed)
 {
 	double min = a[startIndex];
 	int indexOfMin = startIndex;
 	int index;
 	for (index = startIndex + 1; index < numberUsed; index++)
 		if (a[index] < min)
 		{
 			min = a[index];
 			indexOfMin = index;
 			// min is smallest of a[startIndex] through a[index]
 		}
 		return indexOfMin;
 	}
 /**
 Precondition: i and j are legal indices for the array a.
 Postcondition: Values of a[i] and a[j] have been interchanged
 */
 private static void interchange(int i, int j, double [] a)
 {
 	double temp = a[i];
 	a[i] = a[j];
 	a[j] = temp; // original value of a[i]
 }
}