Bubble Sort

CODE

Bubble Sort

Bubble Sort is the simplest sorting algorithm that works by repeatedly swapping the adjacent elements if they are in wrong order.

// C program for implementation of Bubble sort

#include <stdio.h>

void swap(int *xp, int *yp)

{

    int temp = *xp;

    *xp = *yp;

    *yp = temp;

}

// A function to implement bubble sort

void bubbleSort(int arr[], int n)

{

   int i, j;

   for (i = 0; i < n-1; i++)     

       // Last i elements are already in place  

       for (j = 0; j < n-i-1; j++)

           if (arr[j] > arr[j+1])

              swap(&arr[j], &arr[j+1]);

}

/* Function to print an array */

void printArray(int arr[], int size)

{

    int i;

    for (i=0; i < size; i++)

        printf("%d ", arr[i]);

    printf("n");

}

// Driver program to test above functions

int main()

{

    int arr[] = {64, 34, 25, 12, 22, 11, 90};

    int n = sizeof(arr)/sizeof(arr[0]);

    bubbleSort(arr, n);

    printf("Sorted array: \n");

    printArray(arr, n);

    return 0;

}

Output:

Sorted array:

11 12 22 25 34 64 90

Example:

First Pass:

( 5 1 4 2 8 ) –> ( 1 5 4 2 8 ), Here, algorithm compares the first two elements, and swaps since 5 > 1.

( 1 5 4 2 8 ) –>  ( 1 4 5 2 8 ), Swap since 5 > 4

( 1 4 5 2 8 ) –>  ( 1 4 2 5 8 ), Swap since 5 > 2

( 1 4 2 5 8 ) –> ( 1 4 2 5 8 ), Now, since these elements are already in order (8 > 5), algorithm does not swap them.

Second Pass:

( 1 4 2 5 8 ) –> ( 1 4 2 5 8 )

( 1 4 2 5 8 ) –> ( 1 2 4 5 8 ), Swap since 4 > 2

( 1 2 4 5 8 ) –> ( 1 2 4 5 8 )

( 1 2 4 5 8 ) –>  ( 1 2 4 5 8 )

Now, the array is already sorted, but our algorithm does not know if it is completed. The algorithm needs one whole pass without any swap to know it is sorted.

Third Pass:

( 1 2 4 5 8 ) –> ( 1 2 4 5 8 )

( 1 2 4 5 8 ) –> ( 1 2 4 5 8 )

( 1 2 4 5 8 ) –> ( 1 2 4 5 8 )

( 1 2 4 5 8 ) –> ( 1 2 4 5 8 )