Extend collections

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This article describes three enhanced collection template classes, CArrayEx, CMapEx and CSortedArray. CArrayEx and CMapEx each provide an assignment operator and class copy constructor that allow us to easily craft two dimensional arrays and mappings. In addition, CMapEx provides the ability to map CStrings, by providing a template hash function. CSortedArray is a dynamic array template class that provides "sort after insertion" functionality.

  // example of 2 dimensional array

  typedef CArrayEx CIntArray;
  CArrayEx<CIntArray, CIntArray &> a2D;
  CIntArray aInt;
 
  a2D.Add (aInt);    

In a lot of cases we need an array with a find function. We can use a sorted array for this.

To work with arrays of pointers you should use the functions DestructElements, CopyElements as described in the MSDN article 'Collections: How to Make a Type-Safe Collection'], but there exists an alternative way by using auto_ptr:

// auto_ptr example.

CArray,auto_ptr<CValue> > a;
CArray,auto_ptr<CValue> > b;

TRACE(_T("Create\n"));

a.Add(auto_ptr<CValue>(new CValue(1)));
a.Add(auto_ptr<CValue>(new CMyValue(2)));

b.Add(auto_ptr<CValue>(new CValue(3)));
b.Add(auto_ptr<CValue>(new CMyValue(4)));

// TRACE(_T("Copy\n"));

// a.Copy(b);


TRACE(_T("Append\n"));
a.Append(b);

TRACE(_T("Remove all\n"));
b.RemoveAll();

The classes provided with this article are as follows:

CArrayEx

Adds Copy constructor, assign operator and Array compare operators

CMapEx

Adds Copy constructor, assign operator and a method "GetAt" by index. Also adds Hash functions for CString

CListEx

Adds Copy constructor and assign operator

CSortedArray

Adds Copy constructor, assign operator and Array compare operators. Also adds Sorting methods by operators or compare functions