A minimal example of bubble sort, using a character array as an example. (C language practice.)

bubble_sort.c

/* 
   Brandon C. Irizarry

   8/19/21

   Example of Bubble Sort (ascending order).
   
   Upon studying this a bit further, I missed out on
   an invariant of the sort. 
   (The array is always scanned from the beginning each time.)
   
   Should compile as ISO C90.
*/

#include <stdio.h>

typedef enum { FALSE, TRUE } bool;

/* Bubble sort involves performing swaps. */
void swap (char *a, char *b) {
  int temp = *a;
  *a = *b;
  *b = temp;
}

/* When I heard the description, having a separate function for the 
pass step seemed most natural. */
bool run (char array[], size_t n) {
  int i;
  bool sorted = TRUE;
  
  for (i = 0; i < n - 1; i++) {
    if (array[i] > array[i + 1]) {
      swap(&array[i], &array[i + 1]);
      sorted = FALSE;
    }
  }

  return sorted;
}

int main (void) {
  bool sorted = FALSE;
  char name[] = "Brandon";
 
  /* Print my name. */
  printf("%s\n", name);

  /* The actual bubble-sort procedure. Note that we're only sorting up
  to but not including the null-byte. */
  do {
    sorted = run(name, (sizeof name) - 1); 
  } while (!sorted);

  /* Reprint my name, to demonstrate the sorting effect. */
  printf("%s\n", name);

  return 0;
}