public class SelectSort {
   public static void main (String args[]) {
      System.out.println("Select Sort");
      int [] a = {6,4,8,3,1,5,7,2};
      int [] b = a; //copy array by value
      int [] c = a; //it's no fun sorting a sorted array.
      int [] d = a; //now each function uses an unsorted array.

      selectSortUpRL(a);
      System.out.println();
      selectSortDownRL(b);
      System.out.println();
      selectSortUpLR(c);
      System.out.println();
      selectSortDownLR(d);
   }

   //sort in descending order, left to right
   public static void selectSortDownLR(int [] a) {
      for (int i = 0; i < a.length; ++i) { //sort left to right
         System.out.print("sorted index 0 to " + i + ":");
         printArray(a);
         int maxpos = i;
         for (int rem=i+1; rem < a.length; rem++) { //sort left to right
            if (a[rem] > a[maxpos]) //sort in descending order
               maxpos = rem;
         }

         int tmp = a[i];
         a[i] = a[maxpos];
         a[maxpos] = tmp;
      }
   }

   //sort in ascending order, left to right
   public static void selectSortUpLR(int [] a) {
      for (int i = 0; i < a.length; i++) { //sort left to right
         System.out.print("sorted up to index " + i + ":");
         printArray(a);
         int minpos = i;
         for (int rem=i+1; rem < a.length; rem++) { //sort left to right
            if (a[rem] < a[minpos]) //sort in ascending order
               minpos = rem;
         }

         int tmp = a[i];
         a[i] = a[minpos];
         a[minpos] = tmp;
      }
   }  

   //sort in descending order, right to left
   public static void selectSortDownRL(int [] a) {
      for (int i = a.length-1; i >= 0; --i) { //sort right to left
         System.out.print("sorted from index " + i + " to end:");
         printArray(a);
         int maxpos = i;
         for (int rem=i-1; rem >= 0; rem--) { //sort right to left
            if (a[rem] > a[maxpos]) //sort in descending order
               maxpos = rem;
         }

         int tmp = a[i];
         a[i] = a[maxpos];
         a[maxpos] = tmp;
      }
   }

   //sort in ascending order, right to left
   public static void selectSortUpRL(int [] a) {
      for (int i = a.length-1; i >= 0; --i) { //sort left to right
         System.out.print("sorted index " + i + " to end:");
         printArray(a);
         int minpos = i;
         for (int rem=i-1; rem >= 0; rem--) { //sort left to right
            if (a[rem] < a[minpos]) //sort in ascending order
               minpos = rem;
         }

         int tmp = a[i];
         a[i] = a[minpos];
         a[minpos] = tmp;
      }
   }

   public static void printArray (int [] a) {
      for (int i = 0; i < a.length; ++i)
         System.out.print(a[i] + " ");
      System.out.println();
   }
}