This is a pretty simple, straightforward problem, but, of course, I've managed to do something wrong. First, I generated 5 different arrays of 10 random numbers--from 1 to 10, 1 to 100, up to 1 to 100,000. Then I took each array and performed 5 different types of sorts (for a total of 25), calculating the time it takes to perform the sorts. I cannot figure out why each and every result is 0ms regardless of the size of n. What am I doing wrong?
public class Lab16Sorting {
public static void main(String[] args)
{
final int TOTAL_NUMBERS = 10;
int count;
int[] num = new int[TOTAL_NUMBERS];
Random rand = new Random();
// Generate 10 numbers from 1 - 10
System.out.println("SORT 10");
System.out.println("----------------");
for (count = 0; count < TOTAL_NUMBERS; count++)
num[count] = rand.nextInt(10);
System.out.println("Array: " + num);
runSort(num);
// Generate 10 numbers from 1 - 100
System.out.println("\nSORT 100");
System.out.println("----------------");
for (count = 0; count < TOTAL_NUMBERS; count++)
num[count] = rand.nextInt(100);
System.out.println("Array: " + num);
runSort(num);
// Generate 10 numbers from 1 - 1,000
System.out.println("\nSORT 1,000");
System.out.println("----------------");
for (count = 0; count < TOTAL_NUMBERS; count++)
num[count] = rand.nextInt(1000);
System.out.println("Array: " + num);
runSort(num);
// Generate 10 numbers from 1 - 10,000
System.out.println("\nSORT 10,000");
System.out.println("----------------");
for (count = 0; count < TOTAL_NUMBERS; count++)
num[count] = rand.nextInt(10000);
System.out.println("Array: " + num);
runSort(num);
// Generate 10 numbers from 1 - 100,000
System.out.println("\nSORT 100,000");
System.out.println("----------------");
for (count = 0; count < TOTAL_NUMBERS; count++)
num[count] = rand.nextInt(100000);
System.out.println("Array: " + num);
runSort(num);
}
/**
* Run sort algorithms
*/
private static void runSort(int[] num)
{
long before;
long after;
// Run and display selection sort
before = System.currentTimeMillis();
selectionSort(num);
after = System.currentTimeMillis();
System.out.println("Selection sort took "+ (after-before) +" milliseconds");
// Run and display bubble sort
before = System.currentTimeMillis();
bubbleSort(num);
after = System.currentTimeMillis();
System.out.println("Bubble sort took "+ (after-before) +" milliseconds");
// Run and display insertion sort
before = System.currentTimeMillis();
insertionSort(num);
after = System.currentTimeMillis();
System.out.println("Insertion sort took "+ (after-before) +" milliseconds");
// Run and display merge sort
before = System.currentTimeMillis();
mergeSort(num);
after = System.currentTimeMillis();
System.out.println("Merge sort took "+ (after-before) +" milliseconds");
// Run and display quick sort
before = System.currentTimeMillis();
quickSort(num);
after = System.currentTimeMillis();
System.out.println("Quick sort took "+ (after-before) +" milliseconds");
}
I printed out the various array addresses and I see they're all the same (which makes sense since I'm using the same array object). I thought that was the problem and so I tried using different arrays (int[] num, int[] num2...) and I tried re-initializing the array after each runSort() method call with num = new int[TOTAL_NUMBERS].
