Extended Array Template Like CArray

Environment: Generic. Tested on Windows 2000 and Windows Me

CExtendedArray<TYPE, NUM_SORTFLDS, FLDTYPE>

This template implements an abstract MFC style class and provides additional functionality of sorting the data internally over NUM_SORTFLDS simultaneously. Also, class provides ability to search for a given value over these fields quickly, (using binary search) implemented over the sorted fields. It depends on MFC template classes (afxtempl.h) to provide global functions like ConstructElement etc.... If you do not wish to use MFC at all, uncomment all of the functions from top of the file.

It is an abstract class and client must two CompareElem functions. Both of this functions compare two supplied elements and return negative, zero or positive number depending upon whether first element is "less than", "equal to" or "greater than" second element respectively. Only difference between two functions is that in one version, it provides references to two TYPE elements, whereas the second version, passes reference to type and FLDTYPE value.

TYPE

is a data type of object that the CExtArray template will store a pointer to I have done away with ARG_TYPE present in MFC class and all references to object are either converted to a pointer or reference Also, although you can use any field in TYPE, class really becomes useful, when TYPE is a pointer to structure or a class

NUM_SORTFLDS

is a integer value that defines number of fields within the structure, for which you want ability to search and sort data.

FLTDTYPE

is type of field that can be sorted. Only possible value that can make sense here is "void *" or LPARAM. I deliberated a lot on this and cannot think of any other type to use. Send me your comments if you come up with something better. It is basically a place holder that is used while calling CompareElem function.

Sample usage of CExtendedArray<> is as follows:

class something
{
  public:
      char    ApplId[4];
      char    szApplName[81];
};

typedef something* LPSOMESTR;

class MyArray : public CExtendedArray<LPSOMESTR, 2, LPARAM>
{
  int CompareElem(int nSortFld, 
                  LPSOMESTR& first, 
                  LPSOMESTR& second, 
                  LPARAM lHint)
  {
    int r;
    if (nSortFld == 0)
    {
      r = lstrcmpi(first->szApplName, second->szApplName);
      //std::cerr << "Comparing " << first->szApplName 
      //   << " :with: " << second->szApplName 
      //   << "<->" << r << std::endl;
      return r;
    }
    else if (nSortFld == 1)
    {
      return lstrcmpi(first->ApplId , second->ApplId);
      //std::cerr << "Comparing " << first->ApplId 
      // << " :with: " << second->ApplId 
      // << "<->" << r << std::endl;
      return r;
    }

    return 0;
  };

  int CompareElem(int nSortFld, LPSOMESTR& first, 
                  LPARAM valLookup, LPARAM lHint)
  {
    int r;
    if (nSortFld == 0)
    {
      r = lstrcmpi(first->szApplName, (LPCTSTR)valLookup);
      std::cerr << "Comparing " << first->szApplName 
                << " :with: " << (LPCTSTR)valLookup 
                << "<->" << r << std::endl;
      return r;
    }
    else if (nSortFld == 1)
    {
      r = lstrcmpi(first->ApplId , (LPCTSTR)valLookup);
      std::cerr << "Comparing " << first->ApplId 
                << " :with: " << (LPCTSTR)valLookup 
                << "<->" << r << std::endl;
      return r;
    }

    return 0;
  };
};

void testinit()
{
    MyArray wordArray;
    MyArray wordArray2;
    MyArray wordArray3;

    LPSOMESTR w;

    wordArray.SetSize(3,3);

    for (int i = 0; i < 3; i++)
    {
        w = new something;
        // fill in w
        wordArray[i] = w;
    }

    wordArray.SortData(0, 0); // szApplName

    wordArray.SortData(1, 0); // APPL
    LPSOMESTR retVal = NULL;

    if (wordArray.Lookup(1, (LPARAM)"EXT", retVal, 0))
        std::cout << retVal->szApplName << std::endl;

    retVal = NULL;

    if (wordArray.Lookup(1, (LPARAM)"OTH", retVal, 0))
        std::cout << retVal->szApplName << std::endl;
    else
        std::cout << "Not found" << std::endl;
}

Downloads

Download source - 6 Kb


Comments

  • There are no comments yet. Be the first to comment!

Leave a Comment
  • Your email address will not be published. All fields are required.

Top White Papers and Webcasts

  • Flash technology is becoming more prominent in the storage industry. Offering superior speed and reliability when compared to traditional hard disk drives – flash storage is a flexible and increasingly cost-effective technology that can be used to optimize enterprise storage environments. This ebook explores the many uses and benefits of flash storage technology in the enterprise. Check it out to discover and learn all you need to: Optimize storage performance Leverage server flash as storage cache …

  • Managing your company's financials is the backbone of your business and is vital to the long-term health and viability of your company. To continue applying the necessary financial rigor to support rapid growth, the accounting department needs the right tools to most efficiently do their job. Read this white paper to understand the 10 essentials of a complete financial management system and how the right solution can help you keep up with the rapidly changing business world.

Most Popular Programming Stories

More for Developers

Latest Developer Headlines

RSS Feeds