Thread: bubsort working for one text file but not sorting the second file properly

I have a program to read in a set of data from a file, and sort the data in alphabetical order. I use bubsort and within bubsort i use strcmp. When i open file one (5 entries) the program runs fine and all data is sorted alphabetically. However when I open the second file (21 entries) the sorting is not in alphabetical order.
My question is if it works for one file why is it not working for the second? I am beginner programmer.

this is my bubsort code:-
The data being read from the files is of the following form

surname, forename grade
surname1, forename1 grade1
surname2, forename2 grade2
etc........

Code:

/** BUBBLESORT ALGORITHM **/
 
void bubble_sort (student *student_data, int entries)
 
{
 
int j, k;
Boolean exchange_made;
student temp;
k = 1;
exchange_made = TRUE;
int n=entries;
 
/* Make up to (n - 1) passes through array, exit early if no exchanges are made on previous pass */

  while ((k <= entries) && exchange_made)
   {
      exchange_made = FALSE;
               
       for (j = 0; j < n-1; ++j)
       {
         if (strcmp(student_data[j].surname,student_data[j+1].surname)>0)
          {
              /* Number of comparisons on kth pass */

              temp = student_data[j];
              student_data[j] = student_data[j + 1];
              student_data[j + 1] = temp;
              exchange_made = TRUE;
 
              /* Exchange must be made*/
           }

           k++;         
        }
}

I don't see why the k variable is needed, at all. Scrap it, and the first part of the while test. When no exchanges are made, THAT's all you need.

Give that a try.

If you're using the same array, did you clear out the first array's data or know that your number of entries is accurate?

Describe the output you're getting with the second sort?