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1 \section{\class{wxArray}}\label{wxarray}
2
3 This section describes the so called {\it dynamic arrays}. This is a C
4 array-like data structure i.e. the member access time is constant (and not
5 linear according to the number of container elements as for linked lists). However, these
6 arrays are dynamic in the sense that they will automatically allocate more
7 memory if there is not enough of it for adding a new element. They also perform
8 range checking on the index values but in debug mode only, so please be sure to
9 compile your application in debug mode to use it (see \helpref{debugging overview}{debuggingoverview} for
10 details). So, unlike the arrays in some other
11 languages, attempt to access an element beyond the arrays bound doesn't
12 automatically expand the array but provokes an assertion failure instead in
13 debug build and does nothing (except possibly crashing your program) in the
14 release build.
15
16 The array classes were designed to be reasonably efficient, both in terms of
17 run-time speed and memory consumption and the executable size. The speed of
18 array item access is, of course, constant (independent of the number of elements)
19 making them much more efficient than linked lists (\helpref{wxList}{wxlist}).
20 Adding items to the arrays is also implemented in more or less constant time -
21 but the price is preallocating the memory in advance. In the \helpref{memory management}{wxarraymemorymanagement} section
22 you may find some useful hints about optimizing wxArray memory usage. As for executable size, all
23 wxArray functions are inline, so they do not take {\it any space at all}.
24
25 wxWindows has three different kinds of array. All of them derive from
26 wxBaseArray class which works with untyped data and can not be used directly.
27 The standard macros WX\_DEFINE\_ARRAY(), WX\_DEFINE\_SORTED\_ARRAY() and
28 WX\_DEFINE\_OBJARRAY() are used to define a new class deriving from it. The
29 classes declared will be called in this documentation wxArray, wxSortedArray and
30 wxObjArray but you should keep in mind that no classes with such names actually
31 exist, each time you use one of WX\_DEFINE\_XXXARRAY macro you define a class
32 with a new name. In fact, these names are "template" names and each usage of one
33 of the macros mentioned above creates a template specialization for the given
34 element type.
35
36 wxArray is suitable for storing integer types and pointers which it does not
37 treat as objects in any way, i.e. the element pointed to by the pointer is not
38 deleted when the element is removed from the array. It should be noted that
39 all of wxArray's functions are inline, so it costs strictly nothing to define as
40 many array types as you want (either in terms of the executable size or the
41 speed) as long as at least one of them is defined and this is always the case
42 because wxArrays are used by wxWindows internally. This class has one serious
43 limitation: it can only be used for storing integral types (bool, char, short,
44 int, long and their unsigned variants) or pointers (of any kind). An attempt
45 to use with objects of sizeof() greater than sizeof(long) will provoke a
46 runtime assertion failure, however declaring a wxArray of floats will not (on
47 the machines where sizeof(float) <= sizeof(long)), yet it will {\bf not} work,
48 please use wxObjArray for storing floats and doubles (NB: a more efficient
49 wxArrayDouble class is scheduled for the next release of wxWindows).
50
51 wxSortedArray is a wxArray variant which should be used when searching in the
52 array is a frequently used operation. It requires you to define an additional
53 function for comparing two elements of the array element type and always stores
54 its items in the sorted order (according to this function). Thus, it is
55 \helpref{Index()}{wxarrayindex} function execution time is $O(log(N))$ instead of
56 $O(N)$ for the usual arrays but the \helpref{Add()}{wxarrayadd} method is
57 slower: it is $O(log(N))$ instead of constant time (neglecting time spent in
58 memory allocation routine). However, in a usual situation elements are added to
59 an array much less often than searched inside it, so wxSortedArray may lead to
60 huge performance improvements compared to wxArray. Finally, it should be
61 noticed that, as wxArray, wxSortedArray can be only used for storing integral
62 types or pointers.
63
64 wxObjArray class treats its elements like "objects". It may delete them when
65 they are removed from the array (invoking the correct destructor) and copies
66 them using the objects copy constructor. In order to implement this behaviour
67 the definition of the wxObjArray arrays is split in two parts: first, you should
68 declare the new wxObjArray class using WX\_DECLARE\_OBJARRAY() macro and then
69 you must include the file defining the implementation of template type:
70 <wx/arrimpl.cpp> and define the array class with WX\_DEFINE\_OBJARRAY() macro
71 from a point where the full (as opposed to `forward') declaration of the array
72 elements class is in scope. As it probably sounds very complicated here is an
73 example:
74
75 \begin{verbatim}
76 #include <wx/dynarray.h>
77
78 // we must forward declare the array because it is used inside the class
79 // declaration
80 class MyDirectory;
81 class MyFile;
82
83 // this defines two new types: ArrayOfDirectories and ArrayOfFiles which can be
84 // now used as shown below
85 WX_DECLARE_OBJARRAY(MyDirectory, ArrayOfDirectories);
86 WX_DECLARE_OBJARRAY(MyFile, ArrayOfFiles);
87
88 class MyDirectory
89 {
90 ...
91 ArrayOfDirectories m_subdirectories; // all subdirectories
92 ArrayOfFiles m_files; // all files in this directory
93 };
94
95 ...
96
97 // now that we have MyDirectory declaration in scope we may finish the
98 // definition of ArrayOfDirectories -- note that this expands into some C++
99 // code and so should only be compiled once (i.e., don't put this in the
100 // header, but into a source file or you will get linking errors)
101 #include <wx/arrimpl.cpp> // this is a magic incantation which must be done!
102 WX_DEFINE_OBJARRAY(ArrayOfDirectories);
103
104 // that's all!
105 \end{verbatim}
106
107 It is not as elegant as writing
108
109 \begin{verbatim}
110 typedef std::vector<MyDirectory> ArrayOfDirectories;
111 \end{verbatim}
112
113 but is not that complicated and allows the code to be compiled with any, however
114 dumb, C++ compiler in the world.
115
116 Things are much simpler for wxArray and wxSortedArray however: it is enough
117 just to write
118
119 \begin{verbatim}
120 WX_DEFINE_ARRAY(MyDirectory *, ArrayOfDirectories);
121 WX_DEFINE_SORTED_ARRAY(MyFile *, ArrayOfFiles);
122 \end{verbatim}
123
124 \wxheading{See also:}
125
126 \helpref{Container classes overview}{wxcontaineroverview}, \helpref{wxList}{wxlist}
127
128 \wxheading{Include files}
129
130 <wx/dynarray.h> for wxArray and wxSortedArray and additionally <wx/arrimpl.cpp>
131 for wxObjArray.
132
133 \latexignore{\rtfignore{\wxheading{Function groups}}}
134
135 \membersection{Macros for template array definition}
136
137 To use an array you must first define the array class. This is done with the
138 help of the macros in this section. The class of array elements must be (at
139 least) forward declared for WX\_DEFINE\_ARRAY, WX\_DEFINE\_SORTED\_ARRAY and
140 WX\_DECLARE\_OBJARRAY macros and must be fully declared before you use
141 WX\_DEFINE\_OBJARRAY macro.
142
143 \helpref{WX\_DEFINE\_ARRAY}{wxdefinearray}\\
144 \helpref{WX\_DEFINE\_EXPORTED\_ARRAY}{wxdefinearray}\\
145 \helpref{WX\_DEFINE\_USER\_EXPORTED\_ARRAY}{wxdefinearray}\\
146 \helpref{WX\_DEFINE\_SORTED\_ARRAY}{wxdefinesortedarray}\\
147 \helpref{WX\_DEFINE\_SORTED\_EXPORTED\_ARRAY}{wxdefinesortedarray}\\
148 \helpref{WX\_DEFINE\_SORTED\_USER\_EXPORTED\_ARRAY}{wxdefinesortedarray}\\
149 \helpref{WX\_DECLARE\_EXPORTED\_OBJARRAY}{wxdeclareobjarray}\\
150 \helpref{WX\_DECLARE\_USER\_EXPORTED\_OBJARRAY}{wxdeclareobjarray}\\
151 \helpref{WX\_DEFINE\_OBJARRAY}{wxdefineobjarray}\\
152 \helpref{WX\_DEFINE\_EXPORTED\_OBJARRAY}{wxdefineobjarray}\\
153 \helpref{WX\_DEFINE\_USER\_EXPORTED\_OBJARRAY}{wxdefineobjarray}
154
155 \membersection{Constructors and destructors}
156
157 Array classes are 100\% C++ objects and as such they have the appropriate copy
158 constructors and assignment operators. Copying wxArray just copies the elements
159 but copying wxObjArray copies the arrays items. However, for memory-efficiency
160 sake, neither of these classes has virtual destructor. It is not very important
161 for wxArray which has trivial destructor anyhow, but it does mean that you
162 should avoid deleting wxObjArray through a wxBaseArray pointer (as you would
163 never use wxBaseArray anyhow it shouldn't be a problem) and that you should not
164 derive your own classes from the array classes.
165
166 \helpref{wxArray default constructor}{wxarrayctordef}\\
167 \helpref{wxArray copy constructors and assignment operators}{wxarrayctorcopy}\\
168 \helpref{\destruct{wxArray}}{wxarraydtor}
169
170 \membersection{Memory management}\label{wxarraymemorymanagement}
171
172 Automatic array memory management is quite trivial: the array starts by
173 preallocating some minimal amount of memory (defined by
174 WX\_ARRAY\_DEFAULT\_INITIAL\_SIZE) and when further new items exhaust already
175 allocated memory it reallocates it adding 50\% of the currently allocated
176 amount, but no more than some maximal number which is defined by
177 ARRAY\_MAXSIZE\_INCREMENT constant. Of course, this may lead to some memory
178 being wasted (ARRAY\_MAXSIZE\_INCREMENT in the worst case, i.e. 4Kb in the
179 current implementation), so the \helpref{Shrink()}{wxarrayshrink} function is
180 provided to deallocate the extra memory. The \helpref{Alloc()}{wxarrayalloc}
181 function can also be quite useful if you know in advance how many items you are
182 going to put in the array and will prevent the array code from reallocating the
183 memory more times than needed.
184
185 \helpref{Alloc}{wxarrayalloc}\\
186 \helpref{Shrink}{wxarrayshrink}
187
188 \membersection{Number of elements and simple item access}
189
190 Functions in this section return the total number of array elements and allow to
191 retrieve them - possibly using just the C array indexing $[]$ operator which
192 does exactly the same as \helpref{Item()}{wxarrayitem} method.
193
194 \helpref{Count}{wxarraycount}\\
195 \helpref{GetCount}{wxarraygetcount}\\
196 \helpref{IsEmpty}{wxarrayisempty}\\
197 \helpref{Item}{wxarrayitem}\\
198 \helpref{Last}{wxarraylast}
199
200 \membersection{Adding items}
201
202 \helpref{Add}{wxarrayadd}\\
203 \helpref{Insert}{wxarrayinsert}\\
204 \helpref{SetCount}{wxarraysetcount}\\
205 \helpref{WX\_APPEND\_ARRAY}{wxappendarray}
206
207 \membersection{Removing items}
208
209 \helpref{WX\_CLEAR\_ARRAY}{wxcleararray}\\
210 \helpref{Empty}{wxarrayempty}\\
211 \helpref{Clear}{wxarrayclear}\\
212 \helpref{RemoveAt}{wxarrayremoveat}\\
213 \helpref{Remove}{wxarrayremove}
214
215 \membersection{Searching and sorting}
216
217 \helpref{Index}{wxarrayindex}\\
218 \helpref{Sort}{wxarraysort}
219
220 %%%%% MEMBERS HERE %%%%%
221 \helponly{\insertatlevel{2}{
222
223 \wxheading{Members}
224
225 }}
226
227 \membersection{WX\_DEFINE\_ARRAY}\label{wxdefinearray}
228
229 \func{}{WX\_DEFINE\_ARRAY}{\param{}{T}, \param{}{name}}
230
231 \func{}{WX\_DEFINE\_EXPORTED\_ARRAY}{\param{}{T}, \param{}{name}}
232
233 \func{}{WX\_DEFINE\_USER\_EXPORTED\_ARRAY}{\param{}{T}, \param{}{name}, \param{}{exportspec}}
234
235 This macro defines a new array class named {\it name} and containing the
236 elements of type {\it T}. The second form is used when compiling wxWindows as
237 a DLL under Windows and array needs to be visible outside the DLL. The third is
238 needed for exporting an array from a user DLL.
239
240 Example:
241
242 \begin{verbatim}
243 WX_DEFINE_ARRAY(int, wxArrayInt);
244
245 class MyClass;
246 WX_DEFINE_ARRAY(MyClass *, wxArrayOfMyClass);
247 \end{verbatim}
248
249 Note that wxWindows predefines the following standard array classes: wxArrayInt,
250 wxArrayLong and wxArrayPtrVoid.
251
252 \membersection{WX\_DEFINE\_SORTED\_ARRAY}\label{wxdefinesortedarray}
253
254 \func{}{WX\_DEFINE\_SORTED\_ARRAY}{\param{}{T}, \param{}{name}}
255
256 \func{}{WX\_DEFINE\_SORTED\_EXPORTED\_ARRAY}{\param{}{T}, \param{}{name}}
257
258 \func{}{WX\_DEFINE\_SORTED\_USER\_EXPORTED\_ARRAY}{\param{}{T}, \param{}{name}}
259
260 This macro defines a new sorted array class named {\it name} and containing
261 the elements of type {\it T}. The second form is used when compiling wxWindows as
262 a DLL under Windows and array needs to be visible outside the DLL. The third is
263 needed for exporting an array from a user DLL.
264
265 Example:
266
267 \begin{verbatim}
268 WX_DEFINE_SORTED_ARRAY(int, wxSortedArrayInt);
269
270 class MyClass;
271 WX_DEFINE_SORTED_ARRAY(MyClass *, wxArrayOfMyClass);
272 \end{verbatim}
273
274 You will have to initialize the objects of this class by passing a comparison
275 function to the array object constructor like this:
276
277 \begin{verbatim}
278 int CompareInts(int n1, int n2)
279 {
280 return n1 - n2;
281 }
282
283 wxSortedArrayInt sorted(CompareInts);
284
285 int CompareMyClassObjects(MyClass *item1, MyClass *item2)
286 {
287 // sort the items by their address...
288 return Stricmp(item1->GetAddress(), item2->GetAddress());
289 }
290
291 wxArrayOfMyClass another(CompareMyClassObjects);
292 \end{verbatim}
293
294 \membersection{WX\_DECLARE\_OBJARRAY}\label{wxdeclareobjarray}
295
296 \func{}{WX\_DECLARE\_OBJARRAY}{\param{}{T}, \param{}{name}}
297
298 \func{}{WX\_DECLARE\_EXPORTED\_OBJARRAY}{\param{}{T}, \param{}{name}}
299
300 \func{}{WX\_DECLARE\_USER\_EXPORTED\_OBJARRAY}{\param{}{T}, \param{}{name}}
301
302 This macro declares a new object array class named {\it name} and containing
303 the elements of type {\it T}. The second form is used when compiling wxWindows as
304 a DLL under Windows and array needs to be visible outside the DLL. The third is
305 needed for exporting an array from a user DLL.
306
307 Example:
308
309 \begin{verbatim}
310 class MyClass;
311 WX_DECLARE_OBJARRAY(MyClass, wxArrayOfMyClass); // note: not "MyClass *"!
312 \end{verbatim}
313
314 You must use \helpref{WX\_DEFINE\_OBJARRAY()}{wxdefineobjarray} macro to define
315 the array class - otherwise you would get link errors.
316
317 \membersection{WX\_DEFINE\_OBJARRAY}\label{wxdefineobjarray}
318
319 \func{}{WX\_DEFINE\_OBJARRAY}{\param{}{name}}
320
321 \func{}{WX\_DEFINE\_EXPORTED\_OBJARRAY}{\param{}{name}}
322
323 \func{}{WX\_DEFINE\_USER\_EXPORTED\_OBJARRAY}{\param{}{name}}
324
325 This macro defines the methods of the array class {\it name} not defined by the
326 \helpref{WX\_DECLARE\_OBJARRAY()}{wxdeclareobjarray} macro. You must include the
327 file <wx/arrimpl.cpp> before using this macro and you must have the full
328 declaration of the class of array elements in scope! If you forget to do the
329 first, the error will be caught by the compiler, but, unfortunately, many
330 compilers will not give any warnings if you forget to do the second - but the
331 objects of the class will not be copied correctly and their real destructor will
332 not be called. The latter two forms are merely aliases of the first to satisfy
333 some people's sense of symmetry when using the exported declarations.
334
335 Example of usage:
336
337 \begin{verbatim}
338 // first declare the class!
339 class MyClass
340 {
341 public:
342 MyClass(const MyClass&);
343
344 ...
345
346 virtual ~MyClass();
347 };
348
349 #include <wx/arrimpl.cpp>
350 WX_DEFINE_OBJARRAY(wxArrayOfMyClass);
351 \end{verbatim}
352
353 \membersection{WX\_APPEND\_ARRAY}\label{wxappendarray}
354
355 \func{void}{WX\_APPEND\_ARRAY}{\param{wxArray\& }{array}, \param{wxArray\& }{other}}
356
357 This macro may be used to append all elements of the {\it other} array to the
358 {\it array}. The two arrays must be of the same type.
359
360 \membersection{WX\_CLEAR\_ARRAY}\label{wxcleararray}
361
362 \func{void}{WX\_CLEAR\_ARRAY}{\param{wxArray\& }{array}}
363
364 This macro may be used to delete all elements of the array before emptying it.
365 It can not be used with wxObjArrays - but they will delete their elements anyhow
366 when you call Empty().
367
368 \membersection{Default constructors}\label{wxarrayctordef}
369
370 \func{}{wxArray}{\void}
371
372 \func{}{wxObjArray}{\void}
373
374 Default constructor initializes an empty array object.
375
376 \func{}{wxSortedArray}{\param{int (*)(T first, T second)}{compareFunction}}
377
378 There is no default constructor for wxSortedArray classes - you must initialize it
379 with a function to use for item comparison. It is a function which is passed
380 two arguments of type {\it T} where {\it T} is the array element type and which
381 should return a negative, zero or positive value according to whether the first
382 element passed to it is less than, equal to or greater than the second one.
383
384 \membersection{wxArray copy constructor and assignment operator}\label{wxarrayctorcopy}
385
386 \func{}{wxArray}{\param{const wxArray\& }{array}}
387
388 \func{}{wxSortedArray}{\param{const wxSortedArray\& }{array}}
389
390 \func{}{wxObjArray}{\param{const wxObjArray\& }{array}}
391
392 \func{wxArray\&}{operator$=$}{\param{const wxArray\& }{array}}
393
394 \func{wxSortedArray\&}{operator$=$}{\param{const wxSortedArray\& }{array}}
395
396 \func{wxObjArray\&}{operator$=$}{\param{const wxObjArray\& }{array}}
397
398 The copy constructors and assignment operators perform a shallow array copy
399 (i.e. they don't copy the objects pointed to even if the source array contains
400 the items of pointer type) for wxArray and wxSortedArray and a deep copy (i.e.
401 the array element are copied too) for wxObjArray.
402
403 \membersection{wxArray::\destruct{wxArray}}\label{wxarraydtor}
404
405 \func{}{\destruct{wxArray}}{\void}
406
407 \func{}{\destruct{wxSortedArray}}{\void}
408
409 \func{}{\destruct{wxObjArray}}{\void}
410
411 The wxObjArray destructor deletes all the items owned by the array. This is not
412 done by wxArray and wxSortedArray versions - you may use
413 \helpref{WX\_CLEAR\_ARRAY}{wxcleararray} macro for this.
414
415 \membersection{wxArray::Add}\label{wxarrayadd}
416
417 \func{void}{Add}{\param{T }{item}, \param{size\_t}{ copies = $1$}}
418
419 \func{void}{Add}{\param{T *}{item}}
420
421 \func{void}{Add}{\param{T \&}{item}, \param{size\_t}{ copies = $1$}}
422
423 Appends the given number of {\it copies} of the {\it item} to the array
424 consisting of the elements of type {\it T}.
425
426 The first version is used with wxArray and wxSortedArray. The second and the
427 third are used with wxObjArray. There is an important difference between
428 them: if you give a pointer to the array, it will take ownership of it, i.e.
429 will delete it when the item is deleted from the array. If you give a reference
430 to the array, however, the array will make a copy of the item and will not take
431 ownership of the original item. Once again, it only makes sense for wxObjArrays
432 because the other array types never take ownership of their elements. Also note
433 that you cannot append more than one pointer as reusing it would lead to
434 deleting it twice (or more) and hence to a crash.
435
436 You may also use \helpref{WX\_APPEND\_ARRAY}{wxappendarray} macro to append all
437 elements of one array to another one but it is more efficient to use
438 {\it copies} parameter and modify the elements in place later if you plan to
439 append a lot of items.
440
441 \membersection{wxArray::Alloc}\label{wxarrayalloc}
442
443 \func{void}{Alloc}{\param{size\_t }{count}}
444
445 Preallocates memory for a given number of array elements. It is worth calling
446 when the number of items which are going to be added to the array is known in
447 advance because it will save unneeded memory reallocation. If the array already
448 has enough memory for the given number of items, nothing happens.
449
450 \membersection{wxArray::Clear}\label{wxarrayclear}
451
452 \func{void}{Clear}{\void}
453
454 This function does the same as \helpref{Empty()}{wxarrayempty} and additionally
455 frees the memory allocated to the array.
456
457 \membersection{wxArray::Count}\label{wxarraycount}
458
459 \constfunc{size\_t}{Count}{\void}
460
461 Same as \helpref{GetCount()}{wxarraygetcount}. This function is deprecated -
462 it exists only for compatibility.
463
464 \membersection{wxObjArray::Detach}\label{wxobjarraydetach}
465
466 \func{T *}{Detach}{\param{size\_t }{index}}
467
468 Removes the element from the array, but, unlike,
469 \helpref{Remove()}{wxarrayremove} doesn't delete it. The function returns the
470 pointer to the removed element.
471
472 \membersection{wxArray::Empty}\label{wxarrayempty}
473
474 \func{void}{Empty}{\void}
475
476 Empties the array. For wxObjArray classes, this destroys all of the array
477 elements. For wxArray and wxSortedArray this does nothing except marking the
478 array of being empty - this function does not free the allocated memory, use
479 \helpref{Clear()}{wxarrayclear} for this.
480
481 \membersection{wxArray::GetCount}\label{wxarraygetcount}
482
483 \constfunc{size\_t}{GetCount}{\void}
484
485 Return the number of items in the array.
486
487 \membersection{wxArray::Index}\label{wxarrayindex}
488
489 \func{int}{Index}{\param{T\& }{item}, \param{bool }{searchFromEnd = false}}
490
491 \func{int}{Index}{\param{T\& }{item}}
492
493 The first version of the function is for wxArray and wxObjArray, the second is
494 for wxSortedArray only.
495
496 Searches the element in the array, starting from either beginning or the end
497 depending on the value of {\it searchFromEnd} parameter. wxNOT\_FOUND is
498 returned if the element is not found, otherwise the index of the element is
499 returned.
500
501 Linear search is used for the wxArray and wxObjArray classes but binary search
502 in the sorted array is used for wxSortedArray (this is why searchFromEnd
503 parameter doesn't make sense for it).
504
505 {\bf NB:} even for wxObjArray classes, the operator==() of the elements in the
506 array is {\bf not} used by this function. It searches exactly the given
507 element in the array and so will only succeed if this element had been
508 previously added to the array, but fail even if another, identical, element is
509 in the array.
510
511 \membersection{wxArray::Insert}\label{wxarrayinsert}
512
513 \func{void}{Insert}{\param{T }{item}, \param{size\_t }{n}, \param{size\_t }{copies = $1$}}
514
515 \func{void}{Insert}{\param{T *}{item}, \param{size\_t }{n}}
516
517 \func{void}{Insert}{\param{T \&}{item}, \param{size\_t }{n}, \param{size\_t }{copies = $1$}}
518
519 Insert the given number of {\it copies} of the {\it item} into the array before
520 the existing item {\it n} - thus, {\it Insert(something, 0u)} will insert an
521 item in such way that it will become the first array element.
522
523 Please see \helpref{Add()}{wxarrayadd} for explanation of the differences
524 between the overloaded versions of this function.
525
526 \membersection{wxArray::IsEmpty}\label{wxarrayisempty}
527
528 \constfunc{bool}{IsEmpty}{\void}
529
530 Returns true if the array is empty, false otherwise.
531
532 \membersection{wxArray::Item}\label{wxarrayitem}
533
534 \constfunc{T\&}{Item}{\param{size\_t }{index}}
535
536 Returns the item at the given position in the array. If {\it index} is out of
537 bounds, an assert failure is raised in the debug builds but nothing special is
538 done in the release build.
539
540 The returned value is of type "reference to the array element type" for all of
541 the array classes.
542
543 \membersection{wxArray::Last}\label{wxarraylast}
544
545 \constfunc{T\&}{Last}{\void}
546
547 Returns the last element in the array, i.e. is the same as Item(GetCount() - 1).
548 An assert failure is raised in the debug mode if the array is empty.
549
550 The returned value is of type "reference to the array element type" for all of
551 the array classes.
552
553 \membersection{wxArray::Remove}\label{wxarrayremove}
554
555 \func{\void}{Remove}{\param{T }{item}}
556
557 Removes an element from the array by value: the first item of the
558 array equal to {\it item} is removed, an assert failure will result from an
559 attempt to remove an item which doesn't exist in the array.
560
561 When an element is removed from wxObjArray it is deleted by the array - use
562 \helpref{Detach()}{wxobjarraydetach} if you don't want this to happen. On the
563 other hand, when an object is removed from a wxArray nothing happens - you
564 should delete it manually if required:
565
566 \begin{verbatim}
567 T *item = array[n];
568 delete item;
569 array.Remove(n)
570 \end{verbatim}
571
572 See also \helpref{WX\_CLEAR\_ARRAY}{wxcleararray} macro which deletes all
573 elements of a wxArray (supposed to contain pointers).
574
575 \membersection{wxArray::RemoveAt}\label{wxarrayremoveat}
576
577 \func{\void}{RemoveAt}{\param{size\_t }{index}, \param{size\_t }{count = $1$}}
578
579 Removes {\it count} elements starting at {\it index} from the array. When an
580 element is removed from wxObjArray it is deleted by the array - use
581 \helpref{Detach()}{wxobjarraydetach} if you don't want this to happen. On
582 the other hand, when an object is removed from a wxArray nothing happens -
583 you should delete it manually if required:
584
585 \begin{verbatim}
586 T *item = array[n];
587 delete item;
588 array.RemoveAt(n)
589 \end{verbatim}
590
591 See also \helpref{WX\_CLEAR\_ARRAY}{wxcleararray} macro which deletes all
592 elements of a wxArray (supposed to contain pointers).
593
594 \membersection{wxArray::SetCount}\label{wxarraysetcount}
595
596 \func{void}{SetCount}{\param{size\_t }{count}, \param{T }{defval = T($0$)}}
597
598 This function ensures that the number of array elements is at least
599 {\it count}. If the array has already {\it count} or mroe items, nothing is
600 done. Otherwise, {\tt count - GetCount()} elements are added and initialized to
601 the value {\it defval}.
602
603 \wxheading{See also}
604
605 \helpref{GetCount}{wxarraygetcount}
606
607 \membersection{wxArray::Shrink}\label{wxarrayshrink}
608
609 \func{void}{Shrink}{\void}
610
611 Frees all memory unused by the array. If the program knows that no new items
612 will be added to the array it may call Shrink() to reduce its memory usage.
613 However, if a new item is added to the array, some extra memory will be
614 allocated again.
615
616 \membersection{wxArray::Sort}\label{wxarraysort}
617
618 \func{void}{Sort}{\param{CMPFUNC<T> }{compareFunction}}
619
620 The notation CMPFUNC<T> should be read as if we had the following declaration:
621
622 \begin{verbatim}
623 template int CMPFUNC(T *first, T *second);
624 \end{verbatim}
625
626 where {\it T} is the type of the array elements. I.e. it is a function returning
627 {\it int} which is passed two arguments of type {\it T *}.
628
629 Sorts the array using the specified compare function: this function should
630 return a negative, zero or positive value according to whether the first element
631 passed to it is less than, equal to or greater than the second one.
632
633 wxSortedArray doesn't have this function because it is always sorted.
634