15-puzzle: what changed

Revision 1 to 2. Removed lines have a minus sign; added lines have a plus sign.

Old	New		Line
1	1		## 15-puzzle
2	2
3		-	~~<figure>~~
4		-	~~<img src="puzzle15.png" title="puzzle15.png" />~~
5		-	~~<figcaption>puzzle15.png</figcaption>~~
6		-	~~</figure>~~
	3	+	![](/wiki-images/2/20/Puzzle15.png)
7	4
8	5		The 15-puzzle is a sliding puzzle that consists of a frame of numbered square tiles in random order with one tile missing. The object of the puzzle is to place the tiles in order by making sliding moves that use the empty space.
9	6
10	7		## Create code
11	8
12	9		- Create a new blank GUI application with the form [[TForm\|Form1]]
13	10		- Change caption Form1 to 15Puzzle'.
14	11		- Add New [[Unit]] [[15-puzzle\|unitGameBoard.pas]]
15	12		- Create the OnCreate event handler for the form, by clicking on your form, use the Object Inspector, the tab events, select the OnCreate event and click the button \[...\] or double click the button in the form.
16	13		- Add following code:
17	14
18	15		``` pascal
19	16		procedure TForm1.FormCreate(Sender: TObject);
20	17		var
21	18		i : Integer;
22	19		aButton: TButton;
23	20		point:TPoint;
24	21		begin
25	22		Randomize;
26	23		Puzzle15:= TGameBoard.Create;
27	24		i := 1;
28	25		while i < 16 do
29	26		begin //create 15 Buttons
30	27		aButton:=TButton.Create(Self); //create Button, Owner is Form1, where the button is released later
31	28		aButton.Parent:=Self; //determine where it is to be displayed
32	29		aButton.Caption:=IntToStr(i); //Captions of the buttons
33	30		aButton.Width:=aButton.Height; //Width should correspond to the height of the buttons
34	31		point := Puzzle15.ButtonPlace(aButton.Caption);
35	32		aButton.Left:= point.x* aButton.Width; //Distance from left
36	33		aButton.Top := point.y* aButton.Height;
37	34
38	35		aButton.OnClick:=@aButtonClick; //the event handler for the button -> will be created yet
39	36		inc(i);
40	37		end;
41	38		Self.Height:=aButton.Height*6; //Height of the form should correspond to the height of the buttons
42	39		Self.Width:=aButton.Width*6; //Width of the form to match the width of all buttons
43	40		end;
44	41		```
45	42
46	43		- Create in the Object Inspector the event handler for the event FormDestroy, by clicking on the button \[...\].
47	44		- Add the following code to the handler:
48	45
49	46		``` pascal
50	47		procedure TForm1.FormDestroy(Sender: TObject);
51	48		begin
52	49		FreeAndNil(Puzzle15);
53	50		end;
54	51		```
55	52
56	53		- Now you must create the event handler for the button clicks.
57	54		- In the source editor, entering your [[Class\|class]] TForm1 in the section [[Private\|private]].
58		-	- Add [[Procedure\|procedure]] `procedure aButtonClick(Sender: TObject);` and then press the keys <span class="kbd">Ctrl</span>+<span class="kbd">Shift</span>+<span class="kbd">c</span> (the code completion becomes active and creates the `procedure TForm1.aButtonClick(Sender: TObject);`.
	55	+	- Add [[Procedure\|procedure]] `procedure aButtonClick(Sender: TObject);` and then press the keys `Ctrl`+`Shift`+`c` (the code completion becomes active and creates the `procedure TForm1.aButtonClick(Sender: TObject);`.
59	56		- Paste following code:
60	57
61	58		``` pascal
62	59		procedure TForm1.aButtonClick(Sender: TObject); //the event handler for the button
63	60		var
64	61		i:integer;
65	62		point : TPoint;
66	63		begin
67	64		if (Sender is TButton) and //called the event handler of a button out?
68	65		TryStrToInt(TButton(Sender).Caption, i) //then try to convert the label in a integer
69	66		then
70	67		begin
71	68		if Puzzle15.CanMove(TButton(Sender).Caption) then
72	69		begin
73	70		point := Puzzle15.Change(TButton(Sender).Caption);
74	71		TButton(Sender).Left:= point.x* TButton(Sender).Width; //Distance from left
75	72		TButton(Sender).Top := point.y* TButton(Sender).Height;
76	73		end;
77	74		end;
78	75		end;
79	76		```
80	77
81	78		## Source code
82	79
83	80		### unit1.pas
84	81
85	82		``` pascal
86	83		unit Unit1;
87	84
88	85		{$mode objfpc}{$H+}
89	86
90	87		interface
91	88
92	89		uses
93	90		Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, StdCtrls,
94	91		unitGameBoard;
95	92
96	93		type
97	94
98	95		{ TForm1 }
99	96
100	97		TForm1 = class(TForm)
101	98		procedure FormCreate(Sender: TObject);
102	99		procedure FormDestroy(Sender: TObject);
103	100		private
104	101		{ private declarations }
105	102		Puzzle15:TGameBoard;
106	103		procedure aButtonClick(Sender: TObject);
107	104
108	105		public
109	106		{ public declarations }
110	107		end;
111	108
112	109		var
113	110		Form1: TForm1;
114	111
115	112		implementation
116	113
117	114		{$R *.lfm}
118	115
119	116		{ TForm1 }
120	117
121	118		procedure TForm1.FormCreate(Sender: TObject);
122	119		var
123	120		i : Integer;
124	121		aButton: TButton;
125	122		point:TPoint;
126	123		begin
127	124		Randomize;
128	125		Puzzle15:= TGameBoard.Create;
129	126		i := 1;
130	127		while i < 16 do
131	128		begin //create 15 Buttons
132	129		aButton:=TButton.Create(Self); //create Button, Owner is Form1, where the button is released later
133	130		aButton.Parent:=Self; //determine where it is to be displayed
134	131		aButton.Caption:=IntToStr(i); //Captions of the buttons
135	132		aButton.Width:=aButton.Height; //Width should correspond to the height of the buttons
136	133		point := Puzzle15.ButtonPlace(aButton.Caption);
137	134		aButton.Left:= point.x* aButton.Width; //Distance from left
138	135		aButton.Top := point.y* aButton.Height;
139	136		aButton.OnClick:=@aButtonClick; //the event handler for the button -> will be created yet
140	137		inc(i);
141	138		end;
142	139		Self.Height:=aButton.Height*6; //Height of the form should correspond to the height of the buttons
143	140		Self.Width:=aButton.Width*6; //Width of the form to match the width of all buttons
144	141		end;
145	142
146	143		procedure TForm1.FormDestroy(Sender: TObject);
147	144		begin
148	145		FreeAndNil(Puzzle15);
149	146		end;
150	147
151	148		procedure TForm1.aButtonClick(Sender: TObject); //the event handler for the button
152	149		var
153	150		i:integer;
154	151		point : TPoint;
155	152		begin
156	153		if (Sender is TButton) and //called the event handler of a button out?
157	154		TryStrToInt(TButton(Sender).Caption, i) //then try to convert the label in a integer
158	155		then
159	156		begin
160	157		if Puzzle15.CanMove(TButton(Sender).Caption) then
161	158		begin
162	159		point := Puzzle15.Change(TButton(Sender).Caption);
163	160		TButton(Sender).Left:= point.x* TButton(Sender).Width; //Distance from left
164	161		TButton(Sender).Top := point.y* TButton(Sender).Height;
165	162		end;
166	163		end;
167	164		end;
168	165
169	166		end.
170	167		```
171	168
172	169		### Unit1.lfm
173	170
174	171		``` pascal
175	172		object Form1: TForm1
176	173		Left = 362
177	174		Height = 184
178	175		Top = 162
179	176		Width = 432
180	177		Caption = '15Puzzle'
181	178		OnCreate = FormCreate
182	179		OnDestroy = FormDestroy
183	180		LCLVersion = '1.6.0.4'
184	181		end
185	182		```
186	183
187	184		### unitGameBoard.pas
188	185
189	186		``` pascal
190	187		unit unitGameBoard;
191	188
192	189		{$mode objfpc}{$H+}
193	190
194	191		interface
195	192
196	193		uses
197	194		Classes, SysUtils;
198	195
199	196		const
200	197		GB_MAX_BUTTONS = 15;
201	198		GB_MAX_X = 4;
202	199		GB_MAX_Y = 4;
203	200		GB_EMPTY_PLACE ='-';
204	201		type
205	202
206	203		{ TGameBoard }
207	204
208	205		TGameBoard = class
209	206		private
210	207		GameArray:array[1..GB_MAX_X, 1..GB_MAX_Y] of string;
211	208		function ValidPoint(a_point:TPoint):boolean;
212	209		public
213	210		constructor Create;
214	211		function ButtonPlace(a_name:string):TPoint;
215	212		function CanMove(a_name:string):Boolean;
216	213		function Change(a_name: string): TPoint;
217	214		procedure RandomArray;
218	215		destructor Destroy; override;
219	216		end;
220	217		implementation
221	218
222	219		{ TGameBoard }
223	220
224	221		function TGameBoard.ValidPoint(a_point: TPoint): boolean;
225	222		begin
226	223		result := true;
227	224		if a_point.y > GB_MAX_Y then result := false;
228	225		if a_point.x > GB_MAX_X then result := false;
229	226		if a_point.y < 1 then result := false;
230	227		if a_point.x < 1 then result := false;
231	228		end;
232	229
233	230		constructor TGameBoard.Create;
234	231		var
235	232		i, x, y : integer;
236	233		begin
237	234		i := 1;
238	235		for y := 1 to GB_MAX_Y do
239	236		for x := 1 to GB_MAX_X do
240	237		begin
241	238		if i < GB_MAX_BUTTONS+1
242	239		then GameArray[x,y] := IntToStr(i)
243	240		else GameArray[x,y] := GB_EMPTY_PLACE;
244	241		inc(i);
245	242		end;
246	243		RandomArray;
247	244		end;
248	245
249	246		function TGameBoard.ButtonPlace(a_name: string): TPoint;
250	247		var
251	248		x,y:integer;
252	249		begin
253	250		result.x := 0;
254	251		result.y := 0;
255	252		for y := 1 to GB_MAX_Y do
256	253		for x := 1 to GB_MAX_X do
257	254		if GameArray[x,y] = a_name then
258	255		begin
259	256		result.x := x;
260	257		result.y := y;
261	258		end;
262	259		end;
263	260
264	261		function TGameBoard.CanMove(a_name: string): Boolean;
265	262		var
266	263		empty, point:TPoint;
267	264		begin
268	265		result := false;
269	266		empty := ButtonPlace( GB_EMPTY_PLACE );
270	267		point := ButtonPlace(a_name);
271	268		if (abs(empty.x-point.x)=1) and (empty.y=point.y) then result := true;
272	269		if (abs(empty.y-point.y)=1) and (empty.x=point.x) then result := true;
273	270		end;
274	271
275	272		function TGameBoard.Change(a_name: string): TPoint;
276	273		var
277	274		empty, point:TPoint;
278	275		begin
279	276		empty := ButtonPlace( GB_EMPTY_PLACE );
280	277		result := empty;
281	278		point := ButtonPlace(a_name);
282	279		GameArray[point.x, point.y] := '-';
283	280		GameArray[empty.x, empty.y] := a_name;
284	281		end;
285	282
286	283		procedure TGameBoard.RandomArray;
287	284		var
288	285		j,i:integer;
289	286		name:string;
290	287		point,point2:TPoint;
291	288		begin
292	289		for i := 0 to 1000 do
293	290		begin
294	291		j := random(4);
295	292		point := ButtonPlace( GB_EMPTY_PLACE );
296	293		point2 := point;
297	294		case j of
298	295		0: point2.x := point.x-1;
299	296		1: point2.x := point.x+1;
300	297		2: point2.y := point.y-1;
301	298		3: point2.y := point.y+1;
302	299		end;
303	300		if ValidPoint( point2 ) then
304	301		begin
305	302		name := GameArray[point2.x, point2.y];
306	303		GameArray[point.x, point.y] := name;
307	304		GameArray[point2.x, point2.y] := GB_EMPTY_PLACE;
308	305		end;
309	306		end;
310	307		end;
311	308
312	309		destructor TGameBoard.Destroy;
313	310		begin
314	311		inherited Destroy;
315	312		end;
316	313
317	314		end.
318	315		```
319	316
320	317		## See also
321	318
322	319		- [[TButton]]
323	320
324	321		---
325	322		From the Free Pascal wiki, page "15-puzzle", as it stood on 2022-08-06 after a change by Kai Burghardt, out of the wiki's dump of 2024-05-26. Copyright stays with the author who wrote it, according to the old wiki's [[Licensing]] page. If you have concerns about this material, [message the admin](/wiki-contact).

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