Question

I’m trying to sort an array of structs using selection sort and pointers, but I’m having some trouble.

When I try to print the array out to see if the names are sorted, all the names are sorted except for the one in the first position which remains where it is (unsorted).

/*
   all is the unordered array of struct; pLast is pointer to the last struct in array.
*/
void sortArray(CASE* all, CASE* pLast)
{
  CASE* current;
  CASE* walker;
  CASE* smallest;
  CASE temp;


  for(current = all; current < pLast; current++)
  {
    smallest = current;

    for (walker = current + 1; walker <= pLast; walker++)
    {
      if(strcmp(walker->name, smallest->name) < 0 )
        smallest = walker;
    }
    temp = *current;
    *current = *smallest;
    *smallest = temp;
  }

  for(walker = all; walker <= pLast; walker++)
  {
    printf("%s\n", walker->name);
  }  

  return;
}

Any tips?

Thanks

Edit: major revision that allows the names to be printed, but not fully sorted

Answer 1

Being a simple algorithm, selection sorts always look something like this:

function selection_sort(arr):
  for i in 0..len(arr)-1:
    smallest = i
    for j in i+1..len(arr)-1:
      if arr[j] < arr[smallest]:
        smallest = j
    swap i and smallest.

An implementation will still use this format (or very close) if using pointers.

FYI: http://en.wikipedia.org/wiki/Selection_sort