CMapStringToOb Class

Article
04/28/2015

A dictionary collection class that maps unique CString objects to CObject pointers.

class CMapStringToOb : public CObject

Members

Public Constructors

Name	Description
CMapStringToOb::CMapStringToOb	Constructor.

Public Methods

Name	Description
CMapStringToOb::GetCount	Returns the number of elements in this map.
CMapStringToOb::GetHashTableSize	Determines the current number of elements in the hash table.
CMapStringToOb::GetNextAssoc	Gets the next element for iterating.
CMapStringToOb::GetSize	Returns the number of elements in this map.
CMapStringToOb::GetStartPosition	Returns the position of the first element.
CMapStringToOb::HashKey	Calculates the hash value of a specified key.
CMapStringToOb::InitHashTable	Initializes the hash table.
CMapStringToOb::IsEmpty	Tests for the empty-map condition (no elements).
CMapStringToOb::Lookup	Looks up a void pointer based on the void pointer key. The pointer value, not the entity it points to, is used for the key comparison.
CMapStringToOb::LookupKey	Returns a reference to the key associated with the specified key value.
CMapStringToOb::RemoveAll	Removes all the elements from this map.
CMapStringToOb::RemoveKey	Removes an element specified by a key.
CMapStringToOb::SetAt	Inserts an element into the map; replaces an existing element if a matching key is found.

Public Operators

Name	Description
CMapStringToOb::operator [ ]	Inserts an element into the map — operator substitution for SetAt.

Remarks

Once you have inserted a CString-CObject* pair (element) into the map, you can efficiently retrieve or delete the pair using a string or a CString value as a key. You can also iterate over all the elements in the map.

A variable of type POSITION is used for alternate entry access in all map variations. You can use a POSITION to "remember" an entry and to iterate through the map. You might think that this iteration is sequential by key value; it is not. The sequence of retrieved elements is indeterminate.

CMapStringToOb incorporates the IMPLEMENT_SERIAL macro to support serialization and dumping of its elements. Each element is serialized in turn if a map is stored to an archive, either with the overloaded insertion (<<) operator or with the Serialize member function.

If you need a diagnostic dump of the individual elements in the map (the CString value and the CObject contents), you must set the depth of the dump context to 1 or greater.

When a CMapStringToOb object is deleted, or when its elements are removed, the CString objects and the CObject pointers are removed. The objects referenced by the CObject pointers are not destroyed.

Map class derivation is similar to list derivation. See the article Collections for an illustration of the derivation of a special-purpose list class.

Inheritance Hierarchy

CObject

CMapStringToOb

Requirements

Header: afxcoll.h

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