BubbleSort.java

import java.util.Scanner;   // for user input

public class BubbleSort {

    /**
    *   Program:    BubbleSort.java
    *   Purpose:    Sort array using bubblesort routine
    *   Creator:    Chris Clarke
    *   Created:    01.02.2013
    */

    public static void main(String[] args) {
        // create scanner object
        Scanner scan = new Scanner(System.in);
        int i, n;
        int[] a;
        System.out.println("Enter the size of the unsorted array: ");
        do {
            try {
                n = scan.nextInt(); // get user input
            } catch (NumberFormatException e) {
                System.out.println("Must be integer");
                return;
            }//end try/catch
            if (n > 100) System.out.println("Must not be more than 100");
            if (n < 2) System.out.println("Must not be less than 2");
        } while (n > 100 || n < 2);
        a = new int[n];

        System.out.println("Enter each element of the array: ");

        for (i=0; i<n; i++) {
            System.out.print("Enter element "+(i+1)+": ");
            try {
                a[i] = scan.nextInt();
            } catch (NumberFormatException e) {
                System.out.println("Must be integer");
                return;
            }//end try/catch
        }//end for

        //sort the array
        a = sort(a);

        System.out.println("The sorted array looks like this: ");
        for (i=0; i<n; i++) {
            System.out.print(a[i]+" ");
        }
    }//end main

    public static int[] sort(int[] a) {
        // apply bubblesort algorithm to array a
        int i,j,temp;
        int len =a.length;

        for (i=0; i<len-1; i++) {
            for (j=0; j<len-1-i; j++) {
                if (a[j]>a[j+1]) {
                    // swap
                    temp=a[j];
                    a[j]=a[j+1];
                    a[j+1]=temp;
                }//end if
            }//end for j
        }//end for i

        return a;
    }//end sort
}//end class