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Bubble sort in C

Bubble sort in C to arrange numbers in ascending order, you can modify it for descending order and can also sort strings. The bubble sort algorithm isn't efficient as its average-case complexity is O(n2) and worst-case complexity is O(n2). There are many fast sorting algorithms like Quicksort, heap-sort, and others. Sorting simplifies problem-solving in computer programming.

Bubble sort program in C

/* Bubble sort code */

#include <stdio.h>

int main()
{
  int array[100], n, c, d, swap;

  printf("Enter number of elements\n");
  scanf("%d", &n);

  printf("Enter %d integers\n", n);

  for (c = 0; c < n; c++)
    scanf("%d", &array[c]);

  for (c = 0 ; c < n - 1; c++)
  {
    for (d = 0 ; d < n - c - 1; d++)
    {
      if (array[d] > array[d+1]) /* For decreasing order use < */
      {
        swap       = array[d];
        array[d]   = array[d+1];
        array[d+1] = swap;
      }
    }
  }

  printf("Sorted list in ascending order:\n");

  for (c = 0; c < n; c++)
     printf("%d\n", array[c]);

  return 0;
}

Output of program:
Bubble sort C program output

Download Bubble sort program.

Other sorting algorithms:
Selection sort in C
Insertion sort in C

Bubble sort program in C language using function

#include <stdio.h>

void bubble_sort(long [], long);

int main()
{
  long array[100], n, c;

  printf("Enter number of elements\n");
  scanf("%ld", &n);

  printf("Enter %ld integers\n", n);

  for (c = 0; c < n; c++)
    scanf("%ld", &array[c]);

  bubble_sort(array, n);

  printf("Sorted list in ascending order:\n");

  for (c = 0; c < n; c++)
     printf("%ld\n", array[c]);

  return 0;
}

void bubble_sort(long list[], long n)
{
  long c, d, t;

  for (c = 0 ; c < n - 1; c++) {
    for (d = 0 ; d < n - c - 1; d++) {
      if (list[d] > list[d+1]) {
        /* Swapping */
        t         = list[d];
        list[d]   = list[d+1];
        list[d+1] = t;
      }
    }
  }
}

We can use the Bubble Sort algorithm to check if an array is sorted or not. If no swapping takes place, then the array is sorted. We can improve its best-case complexity (if the array is already sorted) to O(n).

#include <stdio.h>

int is_Array_Sorted(int [], int);

int main()
{
  int a[100], n, c;

  printf("Enter number of elements\n");
  scanf("%d", &n);

  printf("Enter %d integers\n", n);

  for (c = 0; c < n; c++)
    scanf("%d", &a[c]);

  if (is_Array_Sorted(a, n))
    printf("The array is sorted.\n");
  else
    printf("The array isn't sorted.\n");

  return 0;
}

int is_Array_Sorted(int a[], int n) {
  int c, d, sorted = 1, t;

  for (c = 0 ; c < n - 1; c++) {
    for (d = 0 ; d < n - c - 1; d++) {
      if (a[d] > a[d+1]) {
        t = a[d];
        a[d] = a[d+1];
        a[d+1] = t;
        return 0;
      }
    }
  }
  return 1;
}