public class Quick { public static int[] Data = { 9, 8, 7, 4, 1, 12, 15, 63, 15, 20 }; public static void quick(int left, int right) { int i, j; int Pivot; int temp; i = left; j = right; Pivot = Data[(left+right)/2]; while (i < j) {  while (Data[i] < Pivot)i++;  while (Data[j] > Pivot) j--;  if (i <= j) {  temp = Data[i];  Data[i] = Data[j];  Data[j] = temp;  i++;  j--;  } } if (left < j)  quick(left, j); if (i < right)  quick(i, right); } public static void main(String[] args) { System.out.println("aaa"); quick(0, 9); System.out.println("bbb"); for (int a = 0; a < Data.length; a++) {  System.out.print(Data[a] + " "); } }}