1  import java.util.Arrays;

  2  import java.util.Scanner;

  3  

  4  /**

  5     This program measures how long it takes to sort an

  6     array of a user-specified size with the Shell

  7     sort algorithm.

  8  */

  9  public class ShellSortTimer

 10  {  

 11     public static void main(String[] args)

 12     {  

 13        Scanner in = new Scanner(System.in);

 14        System.out.print("Enter array size: ");

 15        int n = in.nextInt();

 16  

 17        // Construct random array

 18     

 19        int[] a = ArrayUtil.randomIntArray(n, 100);

 20        int[] a2 = Arrays.copyOf(a, a.length);

 21        int[] a3 = Arrays.copyOf(a, a.length);

 22        

 23        // Use stopwatch to time selection sort

 24        

 25        StopWatch timer = new StopWatch();

 26        

 27        timer.start();

 28        ShellSorter.sort(a);

 29        timer.stop();

 30        

 31        System.out.println("Elapsed time with Shell sort: " 

 32              + timer.getElapsedTime() + " milliseconds");

 33  

 34        timer.reset();

 35        timer.start();

 36        Arrays.sort(a2);

 37        timer.stop();

 38  

 39        System.out.println("Elapsed time with Arrays.sort: " 

 40              + timer.getElapsedTime() + " milliseconds");

 41  

 42        if (!Arrays.equals(a, a2)) 

 43        { 

 44           throw new IllegalStateException("Incorrect sort result"); 

 45        }

 46  

 47        timer.reset();

 48        timer.start();

 49        InsertionSorter.sort(a3);

 50        timer.stop();

 51  

 52        System.out.println("Elapsed time with insertion sort: " 

 53              + timer.getElapsedTime() + " milliseconds");

 54     }

 55  }

 56  

 57