BenchMarker.java

import java.util.Arrays;

/**
 *
 *
 * Simple class for benchmarking some sorting algorithms
 */
public class BenchMarker {
    final static int ARRAY_SIZE = 100_000;

    /**
     * Sorts an unsorted list of integers by using insertion sort
     * @param list an array of integers.
     */
    static void insertionSort(int[] list) {
        int itemsSorted;
        for(itemsSorted = 1; itemsSorted < list.length; itemsSorted++) {
            int temp = list[itemsSorted];
            int loc = itemsSorted - 1;
            while(loc >= 0 && list[loc] > temp) {
                list[loc + 1] = list[loc];
                loc = loc - 1;
            }
            list[loc + 1] = temp;
        }
    }

    /**
     * Sorts an unsorted list of integers by using selection sort
     * @param list an array of integers.
     */
    static void selectionSort(int [] list) {
        for(int first = 0; first < list.length; first++) {

            int smallestLoc = first;

            for(int j = first + 1; j < list.length; j++) {
                if(list[j] < list[smallestLoc]) {
                    smallestLoc = j;
                }
            }

            int temp = list[smallestLoc];
            list[smallestLoc] = list[first];
            list[first] = temp;
        }
    }

    public static void main(String[] args) {
        int[] firstIntList = new int[ARRAY_SIZE];
        int[] secondIntList = new int[ARRAY_SIZE];
        int[] thirdIntList = new int[ARRAY_SIZE];

        long startTime, runTime;

        System.out.println("Creating sample arrays of " + ARRAY_SIZE + " items");

        for(int i = 0; i < ARRAY_SIZE; i++) {
            int item = (int)(Integer.MAX_VALUE * Math.random());
            firstIntList[i] = item;
            secondIntList[i] = item;
            thirdIntList[i] = item;
        }
        System.out.println("======================= DONE ===========================");


        // Sort using selectionSort sort
        System.out.println("Sorting using selection sort");

        startTime = System.currentTimeMillis();
        selectionSort(firstIntList);
        runTime = System.currentTimeMillis() - startTime;

        System.out.println("Selection sort completed in: " + runTime + " Milliseconds");
        System.out.println("======================= DONE ===========================");


        // Sort using insertion sort
        System.out.println("Sorting using insertion sort");

        startTime = System.currentTimeMillis();
        insertionSort(secondIntList);
        runTime = System.currentTimeMillis() - startTime;

        System.out.println("Insertion sort completed in: " + runTime + " Milliseconds");
        System.out.println("======================= DONE ===========================");


        // Sort using Arrays.sort()
        System.out.println("Sorting using in-built Arrays.sort()");

        startTime = System.currentTimeMillis();
        Arrays.sort(thirdIntList);
        runTime = System.currentTimeMillis() - startTime;

        System.out.println("Arrays.sort() sort completed in: " + runTime + " Milliseconds");
        System.out.println("======================= DONE ===========================");
    }
}