Compartir a través de


CList::GetPrev

Gets the list element identified by rPosition, then sets rPosition to the POSITION value of the previous entry in the list.

TYPE& GetPrev(
   POSITION& rPosition 
);
const TYPE& GetPrev( 
   POSITION& rPosition  
) const;

Parameters

  • TYPE
    Template parameter specifying the type of the elements in the list.

  • rPosition
    A reference to a POSITION value returned by a previous GetPrev or other member function call.

Return Value

If the list is const, GetPrev returns a copy of the element at the head of the list. This allows the function to be used only on the right side of an assignment statement and protects the list from modification.

If the list is not const, GetPrev returns a reference to an element of the list. This allows the function to be used on either side of an assignment statement and thus allows the list entries to be modified.

Remarks

You can use GetPrev in a reverse iteration loop if you establish the initial position with a call to GetTailPosition or Find.

You must ensure that your POSITION value represents a valid position in the list. If it is invalid, then the Debug version of the Microsoft Foundation Class Library asserts.

If the retrieved element is the first in the list, then the new value of rPosition is set to NULL.

Example

// Define myList.
CList<CString,CString&> myList;

// Add two elements to the list.
myList.AddHead(CString(_T("ABC")));
myList.AddHead(CString(_T("123")));

// Dump the list elements to the debug window,
// in reverse order.
POSITION pos = myList.GetTailPosition();
for (int i = 0; i < myList.GetCount(); i++)
{
   TRACE(_T("%s\r\n"), (LPCTSTR)myList.GetPrev(pos));
}

Requirements

Header: afxtempl.h

See Also

Reference

CList Class

Hierarchy Chart

CList::Find

CList::GetTailPosition

CList::GetHeadPosition

CList::GetNext

CList::GetHead

Other Resources

CList Members