import java.util.Random;

/** Let's see how long it takes to sort an array.
 *  Let's assume that the command line argument contains how many elements
 *  the user wants in the array.
 */
public class Time2
{
  public static void main(String [] args)
  {
    // First, let's make sure the user is running the program correctly.
    if (args.length == 0)
    {
      System.out.printf("Usage:  java Time2 <number of array elements>\n");
      System.exit(1);
    }

    // The number of array elements is the command-line argument.
    int howMany = Integer.parseInt(args[0]);
    Random g = new Random();

    // Create an array of random numbers.  It's possible some numbers
    // may be repeated, but it shouldn't matter for our experiment.
    int [] a = new int [howMany];
    for (int i = 0; i < howMany; ++i)
      a[i] = g.nextInt(howMany);

    long t1 = System.currentTimeMillis();
    sort(a);
    long t2 = System.currentTimeMillis();
    System.out.printf("It took %d ms to sort %d elements.\n",
                      t2 - t1, howMany);
  }


  /** In CS-12 you'll see much faster ways of sorting an array,
   *  but for now, this one will do.  This is the same way we sorted earlier.
  public static void sort(int [] a)
  {
    for (int i = 0; i < a.length; ++i)
      for (int j = i+1; j < a.length; ++j)
        if (a[i] < a[j])
        {
          int temp = a[i];
          a[i] = a[j];
          a[j] = temp;
        }
  }
}