Bubble sort is one of the simplest sorting algorithms and really intuitive to understand. We compare adjacent elements and see if their order is wrong (a[i] > a[j] for 1 <= i < j <= size of array; if array is to be in ascending order, and vice-versa). If yes, then swap them.
Implementation of Bubble Sort in Java:
import java.util.Scanner;
class BubbleSort {
public static void main(String []args) {
int n;
Scanner in = new Scanner(System.in);
System.out.println("Input number of integers to sort");
n = in.nextInt();
int array[] = new int[n];
System.out.println("Enter " + n + " integers");
for (int i = 0; i < n; i++)
array[i] = in.nextInt();
for (int i = 0; i < n - 1; i++) {
Boolean swapped = false;
for (int j = 0; j < n - i - 1; j++) {
if (array[j] > array[j+1]) /* For descending order use < */
{
int temp = array[j];
array[j]= array[j+1];
array[j+1] = temp;
swapped = true;
}
}
if(!swapped)
break;
}
System.out.println("Sorted list of numbers:");
for (int i = 0; i < n; i++)
System.out.println(array[i]);
}
}
Orignally posted on interviewbit.