QT_校园导航Update

最新推荐文章于 2024-08-04 07:30:00 发布

转载最新推荐文章于 2024-08-04 07:30:00 发布 · 219 阅读

4 ·

CC 4.0 BY-SA版权

原文链接：http://www.cnblogs.com/douzujun/p/6262642.html

本文介绍了一个基于Qt的图形用户界面应用，该应用实现了Dijkstra最短路径算法，并允许用户通过选择不同的起点和终点来查找校园地图上的最短路径。文章详细展示了如何创建界面元素、设置地图场景以及算法的具体实现。

 1 //MainWidget.h
 2 
 3 #ifndef MAINWINDOW_H
 4 #define MAINWINDOW_H
 5 
 6 #include <QMainWindow>
 7 #include "mapwidget.h"
 8 #include <QToolButton>
 9 #include <QGraphicsLineItem>
10 #include <QGraphicsScene>
11 #include <QGraphicsView>
12 #include <QLabel>
13 #include <QComboBox>
14 #include <QSpinBox>
15 #include <QTextEdit>
16 #include <QPainter>
17 #include <QVector>
18 
19 class MainWindow : public QMainWindow
20 {
21     Q_OBJECT
22 public:
23     MainWindow(QWidget *parent = 0);
24     ~MainWindow();
25     void createToolBar();
26     void paintEvent (QPaintEvent *);
27     void setStart(int X, int Y);
28     void setEnd(int X, int Y);
29     void setNextPos (int index);
30     void initScene();
31 public slots:
32     void setStartStation();
33     void setEndStation();
34     void FindPath();
35     void Clear();
36 private:
37     MapWidget *mapWidget;
38     QLabel *startLabel;
39     QLabel *endLabel;
40     QComboBox *startComboBox;
41     QComboBox *endComboBox;
42     QToolButton *findPathBtn;
43     QToolButton *clearBtn;
44 
45     QGraphicsScene *scene;
46     QGraphicsView *view;
47 
48     int startX, startY, endX, endY;
49     QVector<int> nextPath;
50 
51     struct ArcCell{  //弧信息
52         int adj;     //对无权图有1，0表示是否相邻，对带权图，则为权值类型
53     //    string info; //该弧的相关信息
54     };
55 
56     //内部类
57     static const int MAX_VERTEX_NUM = 31;
58     static const int INF = 999999;
59 
60     struct MGraph{
61         QVector<int> vexs;                                    //顶点集合
62         //临接矩阵
63         ArcCell arcs[MAX_VERTEX_NUM][MAX_VERTEX_NUM];
64         int vexnum;                                           //顶点数
65         int arcnum;                                           //边数
66     //    int kind;                                           //图的类型
67     };
68 
69     
70     
71 
72     class DijkstraFindPath
73     {
74     public:
75         DijkstraFindPath();
76         MGraph mgraph;
77         void CreateGraph();
78 //        void ShortestPath(int v0, PathMatrix &path, ShortPathTable &DP, int prev[]);
79         int prev[MAX_VERTEX_NUM];  //最短路上的前驱顶点
80         int d[MAX_VERTEX_NUM];     //表示边e = (u,v)的权值(不存在时为INF,不过d[i][i]=0)
81         bool used[MAX_VERTEX_NUM]; //已经使用过的图
82         void dijkstra(int startPos);      //求从起点startPos出发到各个顶点的最短距离
83         QVector<int> get_Path(int endPos);//到顶点endPos的最短路
84     };
85 
86     DijkstraFindPath *dj;
87 };
88 
89 #endif // MAINWINDOW_H

  1 //MainWidget.cpp
  2 //最短路径算法，和界面的实现
  3 
  4 #include "mainwindow.h"
  5 #include <qdebug.h>
  6 #include <QToolBar>
  7 #include <QtAlgorithms>
  8 #include <iostream>
  9 
 10 MainWindow::MainWindow(QWidget *parent)
 11     : QMainWindow(parent)
 12 {
 13 //    mapWidget = new MapWidget;
 14 //    painter = new QPainter();
 15     dj = new MainWindow::DijkstraFindPath();
 16     dj->CreateGraph ();
 17 
 18     scene = new QGraphicsScene;
 19     scene->setSceneRect (-100, -100, 700, 700);
 20     initScene();
 21 
 22     view = new QGraphicsView;
 23     view->setScene (scene);
 24     view->setMinimumSize (800, 800);
 25     view->show ();
 26     setCentralWidget (view);
 27 
 28     createToolBar ();  //实现一个工具栏
 29 //    setCentralWidget (mapWidget);
 30 //    setMinimumSize (600, 400);  //设置最小尺寸
 31 }
 32 
 33 MainWindow::DijkstraFindPath::DijkstraFindPath()
 34 {
 35     mgraph.vexnum = 31;                      //初始化点数目
 36        for (int i = 0; i < mgraph.vexnum; i++) //初始化点编号
 37            mgraph.vexs.push_back (i);
 38        mgraph.arcnum = 80;                     //暂定
 39        for (int i = 0; i < mgraph.vexnum; i++) {
 40            for (int j = 0; j < mgraph.vexnum; j++) {
 41                if (i == j)
 42                    mgraph.arcs[i][j].adj = 0;
 43                else
 44                    mgraph.arcs[i][j].adj = INF;
 45    //            mgraph.arcs[i][j].info = "";
 46            }
 47        }
 48 }
 49 
 50 void MainWindow::DijkstraFindPath::CreateGraph ()
 51 {
 52         mgraph.arcs[0][1].adj = mgraph.arcs[1][0].adj = 45;    //6 - 5
 53         mgraph.arcs[0][6].adj = mgraph.arcs[6][0].adj = 165;   //6 - 10
 54         mgraph.arcs[1][2].adj = mgraph.arcs[2][1].adj = 45;    //5 - 4
 55         mgraph.arcs[2][3].adj = mgraph.arcs[3][2].adj = 45;    //4 - 3
 56         mgraph.arcs[3][4].adj = mgraph.arcs[4][3].adj = 45;    //3 - 2
 57         mgraph.arcs[3][15].adj = mgraph.arcs[15][3].adj = 24;  //3 - 22
 58         mgraph.arcs[4][5].adj = mgraph.arcs[5][4].adj = 45;    //2 - 1
 59         mgraph.arcs[13][15].adj = mgraph.arcs[15][13].adj = 85;//23 - 22
 60         mgraph.arcs[0][13].adj = mgraph.arcs[13][0].adj = 55;  //6 - 23
 61         mgraph.arcs[13][2].adj = mgraph.arcs[2][13].adj = 50;  //23 - 4
 62         mgraph.arcs[5][11].adj = mgraph.arcs[11][5].adj = 65;  //1 - 一食堂
 63         mgraph.arcs[11][12].adj = mgraph.arcs[12][11].adj = 10;//一食堂-操场
 64         mgraph.arcs[11][27].adj = mgraph.arcs[27][11].adj = 85;//一食堂-祁通1
 65         mgraph.arcs[27][28].adj = mgraph.arcs[28][27].adj = 85;//祁通1-祁通2(路口)
 66         mgraph.arcs[5][29].adj = mgraph.arcs[29][5].adj = 87;  //一食堂-岔路口
 67         mgraph.arcs[29][9].adj = mgraph.arcs[9][29].adj = 80;  //岔路-7
 68         mgraph.arcs[29][11].adj = mgraph.arcs[11][29].adj = 60;//一食堂到岔路(通向7号楼的)
 69         mgraph.arcs[29][30].adj = mgraph.arcs[30][29].adj = 32;//岔路-祁通大道
 70         mgraph.arcs[30][10].adj = mgraph.arcs[10][30].adj = 90;//祁通大道-图书馆
 71         mgraph.arcs[30][28].adj = mgraph.arcs[28][30].adj = 80;//祁通大道-祁通2
 72         mgraph.arcs[28][26].adj = mgraph.arcs[26][28].adj = 15;//祁通2-方肇周
 73         mgraph.arcs[25][27].adj = mgraph.arcs[27][25].adj = 273;    //西大门-祁通1
 74         mgraph.arcs[27][28].adj = mgraph.arcs[28][27].adj = 184;//祁通1-祁通2
 75 //        mgraph.arcs[25][12].adj = mgraph.arcs[12][25].adj = 108; //西大门-西操
 76         mgraph.arcs[5][12].adj = mgraph.arcs[12][5].adj = 70;  //1 - 操场
 77         mgraph.arcs[6][7].adj = mgraph.arcs[7][6].adj = 45;    //10 - 9
 78         mgraph.arcs[7][8].adj = mgraph.arcs[8][7].adj = 45;    //9 - 8
 79         mgraph.arcs[8][9].adj = mgraph.arcs[9][8].adj = 45;    //8 - 7
 80         mgraph.arcs[9][10].adj = mgraph.arcs[10][9].adj = 150; //7 - 图书馆
 81         mgraph.arcs[6][14].adj = mgraph.arcs[14][6].adj = 140; //10 - 13
 82         mgraph.arcs[14][16].adj = mgraph.arcs[16][14].adj = 39;//13 - 12
 83         mgraph.arcs[14][17].adj = mgraph.arcs[17][14].adj = 39;//13 - 16
 84         mgraph.arcs[16][18].adj = mgraph.arcs[18][16].adj = 39;//12 - 15
 85         mgraph.arcs[17][18].adj = mgraph.arcs[18][17].adj = 39;//16 - 15
 86         mgraph.arcs[18][19].adj = mgraph.arcs[19][18].adj = 39;//15 - 14
 87         mgraph.arcs[17][20].adj = mgraph.arcs[20][17].adj = 137;//16 - 19
 88         mgraph.arcs[20][21].adj = mgraph.arcs[21][20].adj = 39; //19 - 18
 89         mgraph.arcs[21][22].adj = mgraph.arcs[22][21].adj = 39; //18 - 17
 90         mgraph.arcs[19][22].adj = mgraph.arcs[22][19].adj = 130;//14 - 17
 91         mgraph.arcs[22][23].adj = mgraph.arcs[23][22].adj = 53; //17 - 二超
 92         mgraph.arcs[23][24].adj = mgraph.arcs[24][23].adj = 5;  //二超 - 二食堂
 93         mgraph.arcs[24][10].adj = mgraph.arcs[10][24].adj = 260;//二食堂-图书馆
 94 
 95         //以下处理细节
 96 
 97 
 98         mgraph.arcnum = 80;
 99 }
100 
101 void MainWindow::DijkstraFindPath::dijkstra (int startPos)
102 {
103     for (int i = 0; i < mgraph.vexnum; i++) d[i] = INF;
104     for (int i = 0; i < mgraph.vexnum; i++) used[i] = false;
105     for (int i = 0; i < mgraph.vexnum; i++) prev[i] = -1;
106     d[startPos] = 0;
107 
108     while (true) {
109         int v = -1;
110         for (int u = 0; u < mgraph.vexnum; u++) {
111             if (!used[u] && (v == -1 || d[u] < d[v])) v = u;
112         }
113 
114         if (v == -1) break;
115         used[v] = true;
116 
117         for (int u = 0; u < mgraph.vexnum; u++) {
118             if (d[u] > d[v] + mgraph.arcs[v][u].adj) {
119                 d[u] = d[v] + mgraph.arcs[v][u].adj;
120                 prev[u] = v;
121             }
122         }
123     }
124 }
125 
126 QVector<int> MainWindow::DijkstraFindPath::get_Path (int endPos)
127 {
128     QVector<int> path;
129 
130     for ( ; endPos != -1; endPos = prev[endPos]) {
131 //        std::cout << "EndPos: " << endPos << ", ";
132         path.push_back (endPos);
133     }
134 
135     std::reverse(path.begin (), path.end ());
136 
137     return path;
138 }
139 
140 void MainWindow::initScene ()
141 {
142     QGraphicsPixmapItem *item =
143             scene->addPixmap (QPixmap("NanTong.jpg"));
144 //    item->setFlag (QGraphicsItem::ItemIsMovable);
145     item->setPos (-500, -420);
146 }
147 
148 MainWindow::~MainWindow()
149 {
150 
151 }
152 
153 void MainWindow::createToolBar ()
154 {
155     QToolBar *toolBar = addToolBar ("Tool");
156     startLabel = new QLabel(tr("起点: "));
157     startComboBox = new QComboBox;
158     startComboBox->addItem (tr("公寓6号楼"));  //0
159     startComboBox->addItem (tr("公寓5号楼"));  //1
160     startComboBox->addItem (tr("公寓4号楼"));  //2
161     startComboBox->addItem (tr("公寓3号楼"));  //3
162     startComboBox->addItem (tr("公寓2号楼"));  //4
163     startComboBox->addItem (tr("公寓1号楼"));  //5
164 
165     startComboBox->addItem (tr("公寓10号楼")); //6
166     startComboBox->addItem (tr("公寓9号楼"));  //7
167     startComboBox->addItem (tr("公寓8号楼"));  //8
168     startComboBox->addItem (tr("公寓7号楼"));  //9
169     startComboBox->addItem (tr("图书馆"));     //10
170     startComboBox->addItem (tr("一食堂")); startComboBox->addItem (tr("西操场"));  //11 12
171     startComboBox->addItem (tr("公寓23号楼")); startComboBox->addItem (tr("公寓13号楼")); //13 14
172     startComboBox->addItem (tr("公寓22号楼")); startComboBox->addItem (tr("公寓12号楼")); //15 16
173     startComboBox->addItem (tr("公寓楼16")); startComboBox->addItem (tr("公寓楼15"));     //17 18
174     startComboBox->addItem (tr("公寓楼14"));  startComboBox->addItem (tr("公寓楼19"));    //19 20
175     startComboBox->addItem (tr("公寓楼18")); startComboBox->addItem (tr("公寓楼17"));     //21 22
176     startComboBox->addItem (tr("二超")); startComboBox->addItem (tr("二食堂"));           //23 24
177     startComboBox->addItem (tr("西大门")); startComboBox->addItem (tr("方肇周教学楼"));    //25 26
178 
179     endLabel = new QLabel(tr("\t终点: "));
180 
181     endComboBox = new QComboBox;
182     endComboBox->addItem (tr("公寓6号楼"));
183     endComboBox->addItem (tr("公寓5号楼"));
184     endComboBox->addItem (tr("公寓4号楼"));
185     endComboBox->addItem (tr("公寓3号楼"));
186     endComboBox->addItem (tr("公寓2号楼"));
187     endComboBox->addItem (tr("公寓1号楼"));
188     endComboBox->addItem (tr("公寓10号楼"));
189     endComboBox->addItem (tr("公寓9号楼"));
190     endComboBox->addItem (tr("公寓8号楼"));
191     endComboBox->addItem (tr("公寓7号楼"));
192     endComboBox->addItem (tr("图书馆"));
193     endComboBox->addItem (tr("一食堂"));    endComboBox->addItem (tr("西操场"));
194     endComboBox->addItem (tr("公寓23号楼"));endComboBox->addItem (tr("公寓13号楼"));
195     endComboBox->addItem (tr("公寓22号楼"));endComboBox->addItem (tr("公寓12号楼"));
196     endComboBox->addItem (tr("公寓楼16"));  endComboBox->addItem (tr("公寓楼15"));
197     endComboBox->addItem (tr("公寓楼14"));  endComboBox->addItem (tr("公寓楼19"));
198     endComboBox->addItem (tr("公寓楼18"));  endComboBox->addItem (tr("公寓楼17"));
199     endComboBox->addItem (tr("二超"));      endComboBox->addItem (tr("二食堂"));
200     endComboBox->addItem (tr("西大门"));    endComboBox->addItem (tr("方肇周教学楼"));
201 
202     connect (startComboBox, SIGNAL(activated(int)), this, SLOT(setStartStation()));
203     connect (endComboBox, SIGNAL(activated(int)), this, SLOT(setEndStation()));
204 
205     findPathBtn = new QToolButton;
206     findPathBtn->setText (tr("\t\t绘制最短路径"));
207 
208     connect (findPathBtn, SIGNAL(clicked(bool)), this, SLOT(FindPath()));
209 
210     clearBtn = new QToolButton;
211     clearBtn->setText (tr("\t\t清除"));
212 
213     connect (clearBtn, SIGNAL(clicked(bool)), this, SLOT(Clear()));
214 
215     toolBar->addWidget (startLabel);
216     toolBar->addWidget (startComboBox);
217     toolBar->addWidget (endLabel);
218     toolBar->addWidget (endComboBox);
219     toolBar->addWidget (findPathBtn);
220     toolBar->addWidget (clearBtn);
221 }
222 
223 void MainWindow::setStart(int X, int Y) {
224     startX = X; startY = Y;
225 //    qDebug() << X << ", " << Y;
226 }
227 
228 void MainWindow::setEnd (int X, int Y)
229 {
230     endX = X; endY = Y;
231 }
232 
233 void MainWindow::setStartStation ()
234 {
235     switch (startComboBox->currentIndex ()) {
236     case 0:
237         setStart(-660, -534); break;
238     case 1:
239         setStart (-673, -490); break;
240     case 2:
241         setStart (-682, -446); break;
242     case 3:
243         setStart (-690, -400); break;
244     case 4:
245         setStart (-701, -355); break;
246     case 5:
247         setStart (-711, -310); break;
248     case 6:
249         setStart (-457, -555); break;
250     case 7:
251         setStart (-449, -485); break;
252     case 8:
253         setStart(-446, -432); break;
254     case 9:
255         setStart (-451, -400); break;
256     case 10:
257         setStart (-347, -353); break;
258     case 11:
259         setStart (-720, -247); break;
260     case 12:
261         setStart (-789, -252); break;
262     case 13:
263         setStart (-721, -517); break;
264     case 14:
265         setStart (-271, -540); break;
266     case 15:
267         setStart (-721, -439); break;
268     case 16:
269         setStart (-274, -495); break;
270     case 17:
271         setStart (-180, -552); break;
272     case 18:
273         setStart (-178, -508); break;
274     case 19:
275         setStart (-179, -456); break;
276     case 20:
277         setStart (-73, -549); break;
278     case 21:
279         setStart (-56, -500); break;
280     case 22:
281         setStart (-59, -448); break;
282     case 23:
283         setStart (-94, -381); break;
284     case 24:
285         setStart (-69, -351); break;
286     case 25:
287         setStart (-1070, -92); break;
288     case 26:
289         setStart (-438, -125); break;
290     case 27:
291         setStart (-721, -119); break;
292     case 28:
293         setStart (-550, -122); break;
294     case 29:
295         setStart (-555, -263); break;
296     case 30:
297         setStart (-498, -235); break;
298     default:
299         break;
300     }
301 }
302 
303 void MainWindow::setEndStation ()
304 {
305     switch (endComboBox->currentIndex ()) {
306     case 0:
307         setEnd(-660, -534); break;
308     case 1:
309         setEnd (-673, -490); break;
310     case 2:
311         setEnd (-682, -446); break;
312     case 3:
313         setEnd (-690, -400); break;
314     case 4:
315         setEnd (-701, -355); break;
316     case 5:
317         setEnd (-711, -310); break;
318     case 6:
319         setEnd (-457, -555); break;
320     case 7:
321         setEnd (-449, -485); break;
322     case 8:
323         setEnd (-446, -432); break;
324     case 9:
325         setEnd (-451, -400); break;
326     case 10:
327         setEnd (-347, -353); break;
328     case 11:
329         setEnd (-720, -247); break;
330     case 12:
331         setEnd (-789, -252); break;
332     case 13:
333         setEnd (-721, -517); break;
334     case 14:
335         setEnd (-271, -540); break;
336     case 15:
337         setEnd (-721, -439); break;
338     case 16:
339         setEnd (-274, -495); break;
340     case 17:
341         setEnd (-180, -552); break;
342     case 18:
343         setEnd (-178, -508); break;
344     case 19:
345         setEnd (-179, -456); break;
346     case 20:
347         setEnd (-73, -549); break;
348     case 21:
349         setEnd (-56, -500); break;
350     case 22:
351         setEnd (-59, -448); break;
352     case 23:
353         setEnd (-94, -381); break;
354     case 24:
355         setEnd (-69, -351); break;
356     case 25:
357         setEnd (-1070, -92); break;
358     case 26:
359         setEnd (-438, -125); break;
360     case 27:
361         setEnd (-721, -119); break;
362     case 28:
363         setEnd (-550, -122); break;
364     case 29:
365         setEnd (-555, -263); break;
366     case 30:
367         setEnd (-498, -235); break;
368     default:
369         break;
370     }
371 }
372 
373 void MainWindow::setNextPos (int index)
374 {
375     switch (index) {
376     case 0:
377         setEnd(-660, -534); break;
378     case 1:
379         setEnd (-673, -490); break;
380     case 2:
381         setEnd (-682, -446); break;
382     case 3:
383         setEnd (-690, -400); break;
384     case 4:
385         setEnd (-701, -355); break;
386     case 5:
387         setEnd (-711, -310); break;
388     case 6:
389         setEnd (-457, -555); break;
390     case 7:
391         setEnd (-449, -485); break;
392     case 8:
393         setEnd (-446, -432); break;
394     case 9:
395         setEnd (-451, -400); break;
396     case 10:
397         setEnd (-347, -353); break;
398     case 11:
399         setEnd (-720, -247); break;
400     case 12:
401         setEnd (-789, -252); break;
402     case 13:
403         setEnd (-721, -517); break;
404     case 14:
405         setEnd (-271, -540); break;
406     case 15:
407         setEnd (-721, -439); break;
408     case 16:
409         setEnd (-274, -495); break;
410     case 17:
411         setEnd (-180, -552); break;
412     case 18:
413         setEnd (-178, -508); break;
414     case 19:
415         setEnd (-179, -456); break;
416     case 20:
417         setEnd (-73, -549); break;
418     case 21:
419         setEnd (-56, -500); break;
420     case 22:
421         setEnd (-59, -448); break;
422     case 23:
423         setEnd (-94, -381); break;
424     case 24:
425         setEnd (-69, -351); break;
426     case 25:
427         setEnd (-1070, -92); break;
428     case 26:
429         setEnd (-438, -125); break;
430     case 27:
431         setEnd (-721, -119); break;
432     case 28:
433         setEnd (-550, -122); break;
434     case 29:
435         setEnd (-555, -263); break;
436     case 30:
437         setEnd (-498, -235); break;
438     default:
439         break;
440     }
441 }
442 
443 void MainWindow::FindPath ()
444 {
445     //Demo 在图片上绘线 在原有基础上 (+700, +440);
446     QVector<QPoint> v;
447 
448     dj->dijkstra (startComboBox->currentIndex ());
449     //设置下一处的终点
450     nextPath = dj->get_Path (endComboBox->currentIndex ());
451 
452     //准备绘制
453     Clear ();
454     //将路线绘制下来
455     QGraphicsPathItem *item = new QGraphicsPathItem();
456 
457     QPen pen;
458     pen.setWidth (4);
459     pen.setColor (Qt::red);
460     item->setPen (pen);
461     item->setFlag (QGraphicsItem::ItemIsPanel);
462 
463 //    qDebug() << startX << " " << startY << " " << endX << " " << endY;
464 
465 //    qDebug() << "Hello World !";
466 
467     //设置起点
468 //    v << QPoint(startX + 700, startY + 440);
469 
470     for (int i = 1; i < nextPath.size (); i++) {
471         qDebug() << nextPath[i] << " , ";
472     }
473     scene->addItem (item);
474 
475     QPainterPath pa;               //path
476 //    setNextPos (nextPath[1]);
477 //    item->setLine (startX + 700, startY + 440, endX + 700, endY + 440);
478     pa.moveTo (startX + 700, startY + 440);
479 
480     for (int i = 1; i < nextPath.size() ; i++) {
481         setNextPos (nextPath[i]);
482         pa.lineTo (endX + 700, endY + 440);
483     }
484     item->setPath (pa);
485 
486 }
487 
488 void MainWindow::Clear ()
489 {
490     QList<QGraphicsItem*> listItem = scene->items ();
491     while (!listItem.empty ())
492     {
493         scene->removeItem (listItem.at (0));
494         listItem.removeAt (0);
495     }
496     QGraphicsPixmapItem *item =
497             scene->addPixmap (QPixmap("NanTong.jpg"));
498 //    item->setFlag (QGraphicsItem::ItemIsMovable);
499     item->setPos (-500, -420);
500 }
501 
502 void MainWindow::paintEvent (QPaintEvent *)
503 {
504 
505 }

 1 //Main.cpp
 2 #include "mainwindow.h"
 3 #include "mapwidget.h"
 4 #include <QApplication>
 5 #include <QFont>
 6 #include <QDebug>
 7 
 8 int main(int argc, char *argv[])
 9 {
10     QApplication a(argc, argv);
11     QFont font("ARPL KaitiM GB", 12);
12     font.setBold (true);
13     a.setFont (font);
14 
15     qDebug() << "Run............";
16     MainWindow w;
17     w.show ();
18 
19 
20     return a.exec();
21 }

转载于:https://www.cnblogs.com/douzujun/p/6262642.html