Re: Sorting a CObArray?

From: Adrian Gibbons (adriangibbons_at_yahoo.co.uk)
Date: 03/27/04 

Date: 27 Mar 2004 11:07:25 -0800

Thanks for your replies. I've actually found a solution to my problem
from a posting back in 1997:

Google Groups link: http://groups.google.co.uk/groups?hl=en&lr=&ie=UTF-8&oe=UTF-8&selm=01bc7518%248dac3770%248adffe26%40tthomaspc

From: H. Tom Thomas (tthomas@seabase.com)
Subject: Re: sorted array
Newsgroups: microsoft.public.vc.mfc
Date: 1997/06/09

(EDITED)

Here is some code that does the trick. Derive a class from CObArray
with a
pure virtual function that you implement based on the attribute you
want to
sort.

// SortObArray.h
class CSortObArray : public CObArray
{
  DECLARE_DYNAMIC(CSortObArray)
public:
  CSortObArray();
  void Sort();
private:
  virtual BOOL CompareAndSwap(int pos) = 0;
};

// SortObArray.cpp
#include "stdafx.h"
#include "SortObArray.h"

IMPLEMENT_DYNAMIC(CSortObArray, CObArray)

CSortObArray::CSortObArray() : CObArray()
{
}

// Sort
void CSortObArray::Sort()
{
  BOOL bNotDone = TRUE;
 
  while (bNotDone)
  {
    bNotDone = FALSE;
    for(int pos = 0;pos < GetUpperBound();pos++)
      bNotDone |= CompareAndSwap(pos);
  }
}

// CompareAndSwap write this according to your needs
BOOL CSortObArray_DerivedClass::CompareAndSwap(int pos)
{
  CObject* temp;
  int posFirst = pos;
  int posNext = pos + 1;

  if(((CSomeObj*)GetAt(posFirst))->m_sKey.CompareNoCase(((CSomeObj*)GetAt(posNext))->m_sKey)
> 0)
  {
    temp = GetAt(posFirst);
    SetAt(posFirst, GetAt(posNext));
    SetAt(posNext, temp);
    return TRUE;
  }

  return FALSE;
}

For my implementation of CompareAndSwap() I've replaced "CSomeObj*"
with "CStringArray*" and "m_sKey" with "GetAt(0)" to compare the first
CString in the CStringArrays. I also moved the "CObject* temp" into
the IF structure and replaced it with "CStringArray* temp =
(CStringArray*)GetAt(posFirst)".

Due to the time pressures on my project and the fact that I do not
know STL already, this is a good enough solution for me. Maybe I'll
have a look at doing it using vectors and the STL in the future.

Hope this is of some help to people of the future :)

Adrian.

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