CTypedPtrMap Class

 

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Provides a type-safe "wrapper" for objects of the pointer-map classes CMapPtrToPtr, CMapPtrToWord, CMapWordToPtr, and CMapStringToPtr.

Syntax

template<class BASE_CLASS, class KEY, class VALUE>  
class CTypedPtrMap : public BASE_CLASS  

Parameters

BASE_CLASS
Base class of the typed pointer map class; must be a pointer map class ( CMapPtrToPtr, CMapPtrToWord, CMapWordToPtr, or CMapStringToPtr).

KEY
Class of the object used as the key to the map.

VALUE
Class of the object stored in the map.

Members

Public Methods

Name	Description
CTypedPtrMap::GetNextAssoc	Gets the next element for iterating.
CTypedPtrMap::Lookup	Returns a KEY based on a VALUE.
CTypedPtrMap::RemoveKey	Removes an element specified by a key.
CTypedPtrMap::SetAt	Inserts an element into the map; replaces an existing element if a matching key is found.

Public Operators

Name	Description
CTypedPtrMap::operator [ ]	Inserts an element into the map.

Remarks

When you use CTypedPtrMap, the C++ type-checking facility helps eliminate errors caused by mismatched pointer types.

Because all CTypedPtrMap functions are inline, use of this template does not significantly affect the size or speed of your code.

For more information on using CTypedPtrMap, see the articles Collections and Template-Based Classes.

Inheritance Hierarchy

BASE_CLASS

CTypedPtrMap

Requirements

Header: afxtempl.h

CTypedPtrMap::GetNextAssoc

Retrieves the map element at rNextPosition, then updates rNextPosition to refer to the next element in the map.

void GetNextAssoc(
    POSITION& rPosition,
    KEY& rKey,
    VALUE& rValue) const;  

Parameters

rPosition
Specifies a reference to a POSITION value returned by a previous GetNextAssoc or BASE_CLASS::GetStartPosition call.

KEY
Template parameter specifying the type of the map's keys.

rKey
Specifies the returned key of the retrieved element.

VALUE
Template parameter specifying the type of the map's values.

rValue
Specifies the returned value of the retrieved element.

Remarks

This function is most useful for iterating through all the elements in the map. Note that the position sequence is not necessarily the same as the key value sequence.

If the retrieved element is the last in the map, then the new value of rNextPosition is set to NULL.

This inline function calls BASE_CLASS::GetNextAssoc.

CTypedPtrMap::Lookup

Lookup uses a hashing algorithm to quickly find the map element with a key that matches exactly.

BOOL Lookup(BASE_CLASS ::BASE_ARG_KEY key, VALUE& rValue) const;  

Parameters

BASE_CLASS
Template parameter specifying the base class of this map's class.

key
The key of the element to be looked up.

VALUE
Template parameter specifying the type of values stored in this map.

rValue
Specifies the returned value of the retrieved element.

Return Value

Nonzero if the element was found; otherwise 0.

Remarks

This inline function calls BASE_CLASS::Lookup.

CTypedPtrMap::operator [ ]

This operator can be used only on the left side of an assignment statement (an l-value).

VALUE& operator[](BASE_CLASS ::BASE_ARG_KEY key);

Parameters

VALUE
Template parameter specifying the type of values stored in this map.

BASE_CLASS
Template parameter specifying the base class of this map's class.

key
The key of the element to be looked up or created in the map.

Remarks

If there is no map element with the specified key, then a new element is created. There is no "right side" (r-value) equivalent to this operator because there is a possibility that a key may not be found in the map. Use the Lookup member function for element retrieval.

CTypedPtrMap::RemoveKey

This member function calls BASE_CLASS::RemoveKey.

BOOL RemoveKey(KEY key);

Parameters

KEY
Template parameter specifying the type of the map's keys.

key
Key for the element to be removed.

Return Value

Nonzero if the entry was found and successfully removed; otherwise 0.

Remarks

For more detailed remarks, see CMapStringToOb::RemoveKey.

CTypedPtrMap::SetAt

This member function calls BASE_CLASS::SetAt.

void SetAt(KEY key, VALUE newValue);

Parameters

KEY
Template parameter specifying the type of the map's keys.

key
Specifies the key value of the newValue.

newValue
Specifies the object pointer that is the value of the new element.

Remarks

For more detailed remarks, see CMapStringToOb::SetAt.

See Also

MFC Sample COLLECT
Hierarchy Chart
CMapPtrToPtr Class
CMapPtrToWord Class
CMapWordToPtr Class
CMapStringToPtr Class