This class provides linked list functionality for wxWindows, and for an application if it wishes. Depending on the form of constructor used, a list can be keyed on integer or string keys to provide a primitive look-up ability. See wxHashTable for a faster method of storage when random access is required.
It is very common to iterate on a list as follows:
... wxPoint *point1 = new wxPoint(100, 100); wxPoint *point2 = new wxPoint(200, 200); wxList SomeList; SomeList.Append(point1); SomeList.Append(point2); ... wxNode *node = SomeList.First(); while (node) { wxPoint *point = (wxPoint *)node->Data(); ... node = node->Next(); }To delete nodes in a list as the list is being traversed, replace
... node = node->Next(); ...with
... delete point; delete node; node = SomeList.First(); ...See wxNode for members that retrieve the data associated with a node, and members for getting to the next or previous node.
Note that a cast is required when retrieving the data from a node. Although a node is defined to store objects of type wxObject and derived types, other types (such as char *) may be used with appropriate casting.
wxList::wxList
wxList::~wxList
wxList::Append
wxList::Clear
wxList::DeleteContents
wxList::DeleteNode
wxList::DeleteObject
wxList::Find
wxList::First
wxList::Insert
wxList::Last
wxList::Member
wxList::Nth
wxList::Number
wxList::Sort
void wxList(void)
void wxList(unsigned int key_type)
void wxList(int n, wxObject *objects[])
void wxList(wxObject *object, ...)
Constructors. key_type is one of wxKEY_NONE, wxKEY_INTEGER, or wxKEY_STRING, and indicates what sort of keying is required (if any).
objects is an array of n objects with which to initialize the list.
The variable-length argument list constructor must be supplied with a terminating NULL.
void ~wxList(void)
Destroys list. Also destroys any remaining nodes, but does not destroy client data held in the nodes.
wxNode * Append(wxObject *object)
wxNode * Append(long key, wxObject *object)
wxNode * Append(char *key, wxObject *object)
Appends a new wxNode to the end of the list and puts a pointer to the object in the node. The last two forms store a key with the object for later retrieval using the key. The new node is returned in each case.
The key string is copied and stored by the list implementation.
void Clear(void)
Clears the list (but does not delete the client data stored with each node).
void DeleteContents(Bool destroy)
If destroy is TRUE, instructs the list to call delete on the client contents of a node whenever the node is destroyed. The default is FALSE.
Bool DeleteNode(wxNode *node)
Deletes the given node from the list, returning TRUE if successful.
Bool DeleteObject(wxObject *object)
Finds the given client object and deletes the appropriate node from the list, returning TRUE if successful. The application must delete the actual object separately.
wxNode * Find(long key)
wxNode * Find(char *key)
Returns the node whose stored key matches key. Use on a keyed list only.
wxNode * First(void)
Returns the first node in the list (NULL if the list is empty).
wxNode * Insert(wxObject *object)
Insert object at front of list.
wxNode * Insert(wxNode *position, wxObject *object)
Insert object before position.
wxNode * Last(void)
Returns the last node in the list (NULL if the list is empty).
wxNode * Member(wxObject *object)
Returns the node associated with object if it is in the list, NULL otherwise.
wxNode * Nth(int n)
Returns the nth node in the list, indexing from zero (NULL if the list is empty or the nth node could not be found).
int Number(void)
Returns the number of elements in the list.
void Sort(wxSortCompareFunction compfunc)
// Type of compare function for list sort operation (as in 'qsort') typedef int (*wxSortCompareFunction)(const void *elem1, const void *elem2);Allows the sorting of arbitrary lists by giving a function to compare two list elements. We use the system qsort function for the actual sorting process. The sort function receives pointers to wxObject pointers (wxObject **), so be careful to dereference appropriately.
Example:
int listcompare(const void *arg1, const void *arg2) { return(compare(**(wxString **)arg1, // use the wxString 'compare' **(wxString **)arg2)); // function } void main() { wxList list; list.Append(new wxString("DEF")); list.Append(new wxString("GHI")); list.Append(new wxString("ABC")); list.Sort(listcompare); }