&是一个位运算符，就是将两个二进制的数逐位相与，就是都是1才是1，只要有一个为0则为0，结果是相与之后的结果。
&&是一个逻辑运算符，就是判断两个表达式的真假性，只有两个表达式同时为真才为真，有一个为假则为假，具有短路性质。
1 /*-------------------------------------------------
2 CHECKER4.C -- Mouse Hit-Test Demo Program No. 4
3 (c) Charles Petzold, 1998
4 -------------------------------------------------*/
5
6 #include <windows.h>
7
8 #define DIVISIONS 5
9
10 LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;
11 LRESULT CALLBACK ChildWndProc (HWND, UINT, WPARAM, LPARAM) ;
12
13 int idFocus = 0 ;
14 TCHAR szChildClass[] = TEXT ("Checker4_Child") ;
15
16 int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
17 PSTR szCmdLine, int iCmdShow)
18 {
19 static TCHAR szAppName[] = TEXT ("Checker4") ;
20 HWND hwnd ;
21 MSG msg ;
22 WNDCLASS wndclass ;
23
24 wndclass.style = CS_HREDRAW | CS_VREDRAW ;
25 wndclass.lpfnWndProc = WndProc ;
26 wndclass.cbClsExtra = 0 ;
27 wndclass.cbWndExtra = 0 ;
28 wndclass.hInstance = hInstance ;
29 wndclass.hIcon = LoadIcon (NULL, IDI_APPLICATION) ;
30 wndclass.hCursor = LoadCursor (NULL, IDC_ARROW) ;
31 wndclass.hbrBackground = (HBRUSH) GetStockObject (WHITE_BRUSH) ;
32 wndclass.lpszMenuName = NULL ;
33 wndclass.lpszClassName = szAppName ;
34
35 if (!RegisterClass (&wndclass))
36 {
37 MessageBox (NULL, TEXT ("Program requires Windows NT!"),
38 szAppName, MB_ICONERROR) ;
39 return 0 ;
40 }
41
42 wndclass.lpfnWndProc = ChildWndProc ;
43 wndclass.cbWndExtra = sizeof (long) ;
44 wndclass.hIcon = NULL ;
45 wndclass.lpszClassName = szChildClass ;
46
47 RegisterClass (&wndclass) ;
48
49 hwnd = CreateWindow (szAppName, TEXT ("Checker4 Mouse Hit-Test Demo"),
50 WS_OVERLAPPEDWINDOW,
51 CW_USEDEFAULT, CW_USEDEFAULT,
52 CW_USEDEFAULT, CW_USEDEFAULT,
53 NULL, NULL, hInstance, NULL) ;
54
55 ShowWindow (hwnd, iCmdShow) ;
56 UpdateWindow (hwnd) ;
57
58 while (GetMessage (&msg, NULL, 0, 0))
59 {
60 TranslateMessage (&msg) ;
61 DispatchMessage (&msg) ;
62 }
63 return msg.wParam ;
64 }
65
66 LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
67 {
68 static HWND hwndChild[DIVISIONS][DIVISIONS] ;
69 int cxBlock, cyBlock, x, y ;
70
71 switch (message)
72 {
73 case WM_CREATE :
74 for (x = 0 ; x < DIVISIONS ; x++)
75 for (y = 0 ; y < DIVISIONS ; y++)
76 hwndChild[x][y] = CreateWindow (szChildClass, NULL,
77 WS_CHILDWINDOW | WS_VISIBLE,
78 0, 0, 0, 0,
79 hwnd, (HMENU) (y << 8 | x),
80 (HINSTANCE) GetWindowLong (hwnd, GWL_HINSTANCE),
81 NULL) ;
82 return 0 ;
83
84 case WM_SIZE :
85 cxBlock = LOWORD (lParam) / DIVISIONS ;
86 cyBlock = HIWORD (lParam) / DIVISIONS ;
87
88 for (x = 0 ; x < DIVISIONS ; x++)
89 for (y = 0 ; y < DIVISIONS ; y++)
90 MoveWindow (hwndChild[x][y],
91 x * cxBlock, y * cyBlock,
92 cxBlock, cyBlock, TRUE) ;
93 return 0 ;
94
95 case WM_LBUTTONDOWN :
96 MessageBeep (0) ;
97 return 0 ;
98
99 // On set-focus message, set focus to child window
100
101 case WM_SETFOCUS:
102 SetFocus (GetDlgItem (hwnd, idFocus)) ;
103 return 0 ;
104
105 // On key-down message, possibly change the focus window
106
107 case WM_KEYDOWN:
108 x = idFocus & 0xFF ;
109 y = idFocus >> 8 ;
110
111 switch (wParam)
112 {
113 case VK_UP: y-- ; break ;
114 case VK_DOWN: y++ ; break ;
115 case VK_LEFT: x-- ; break ;
116 case VK_RIGHT: x++ ; break ;
117 case VK_HOME: x = y = 0 ; break ;
118 case VK_END: x = y = DIVISIONS - 1 ; break ;
119 default: return 0 ;
120 }
121
122 x = (x + DIVISIONS) % DIVISIONS ;
123 y = (y + DIVISIONS) % DIVISIONS ;
124
125 idFocus = y << 8 | x ;
126
127 SetFocus (GetDlgItem (hwnd, idFocus)) ;
128 return 0 ;
129
130 case WM_DESTROY :
131 PostQuitMessage (0) ;
132 return 0 ;
133 }
134 return DefWindowProc (hwnd, message, wParam, lParam) ;
135 }
136
137 LRESULT CALLBACK ChildWndProc (HWND hwnd, UINT message,
138 WPARAM wParam, LPARAM lParam)
139 {
140 HDC hdc ;
141 PAINTSTRUCT ps ;
142 RECT rect ;
143
144 switch (message)
145 {
146 case WM_CREATE :
147 SetWindowLong (hwnd, 0, 0) ; // on/off flag
148 return 0 ;
149
150 case WM_KEYDOWN:
151 // Send most key presses to the parent window
152
153 if (wParam != VK_RETURN && wParam != VK_SPACE)
154 {
155 SendMessage (GetParent (hwnd), message, wParam, lParam) ;
156 return 0 ;
157 }
158 // For Return and Space, fall through to toggle the square
159
160 case WM_LBUTTONDOWN :
161 SetWindowLong (hwnd, 0, 1 ^ GetWindowLong (hwnd, 0)) ;
162 SetFocus (hwnd) ;
163 InvalidateRect (hwnd, NULL, FALSE) ;
164 return 0 ;
165
166 // For focus messages, invalidate the window for repaint
167
168 case WM_SETFOCUS:
169 idFocus = GetWindowLong (hwnd, GWL_ID) ;
170
171 // Fall through
172
173 case WM_KILLFOCUS:
174 InvalidateRect (hwnd, NULL, TRUE) ;
175 return 0 ;
176
177 case WM_PAINT :
178 hdc = BeginPaint (hwnd, &ps) ;
179
180 GetClientRect (hwnd, &rect) ;
181 Rectangle (hdc, 0, 0, rect.right, rect.bottom) ;
182
183 // Draw the "x" mark
184
185 if (GetWindowLong (hwnd, 0))
186 {
187 MoveToEx (hdc, 0, 0, NULL) ;
188 LineTo (hdc, rect.right, rect.bottom) ;
189 MoveToEx (hdc, 0, rect.bottom, NULL) ;
190 LineTo (hdc, rect.right, 0) ;
191 }
192
193 // Draw the "focus" rectangle
194
195 if (hwnd == GetFocus ())
196 {
197 rect.left += rect.right / 10 ;
198 rect.right -= rect.left ;
199 rect.top += rect.bottom / 10 ;
200 rect.bottom -= rect.top ;
201
202 SelectObject (hdc, GetStockObject (NULL_BRUSH)) ;
203 SelectObject (hdc, CreatePen (PS_DASH, 0, 0)) ;
204 Rectangle (hdc, rect.left, rect.top, rect.right, rect.bottom) ;
205 DeleteObject (SelectObject (hdc, GetStockObject (BLACK_PEN))) ;
206 }
207
208 EndPaint (hwnd, &ps) ;
209 return 0 ;
210 }
211 return DefWindowProc (hwnd, message, wParam, lParam) ;
212 }
1 /*-------------------------------------------------
2 CHECKER4.C -- Mouse Hit-Test Demo Program No. 4
3 (c) Charles Petzold, 1998
4 -------------------------------------------------*/
5
6 #include <windows.h>
7
8 #define DIVISIONS 5
9
10 LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;
11 LRESULT CALLBACK ChildWndProc (HWND, UINT, WPARAM, LPARAM) ;
12
13 int idFocus = 0 ;
14 TCHAR szChildClass[] = TEXT ("Checker4_Child") ;
15
16 int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
17 PSTR szCmdLine, int iCmdShow)
18 {
19 static TCHAR szAppName[] = TEXT ("Checker4") ;
20 HWND hwnd ;
21 MSG msg ;
22 WNDCLASS wndclass ;
23
24 wndclass.style = CS_HREDRAW | CS_VREDRAW ;
25 wndclass.lpfnWndProc = WndProc ;
26 wndclass.cbClsExtra = 0 ;
27 wndclass.cbWndExtra = 0 ;
28 wndclass.hInstance = hInstance ;
29 wndclass.hIcon = LoadIcon (NULL, IDI_APPLICATION) ;
30 wndclass.hCursor = LoadCursor (NULL, IDC_ARROW) ;
31 wndclass.hbrBackground = (HBRUSH) GetStockObject (WHITE_BRUSH) ;
32 wndclass.lpszMenuName = NULL ;
33 wndclass.lpszClassName = szAppName ;
34
35 if (!RegisterClass (&wndclass))
36 {
37 MessageBox (NULL, TEXT ("Program requires Windows NT!"),
38 szAppName, MB_ICONERROR) ;
39 return 0 ;
40 }
41
42 wndclass.lpfnWndProc = ChildWndProc ;
43 wndclass.cbWndExtra = sizeof (long) ;
44 wndclass.hIcon = NULL ;
45 wndclass.lpszClassName = szChildClass ;
46
47 RegisterClass (&wndclass) ;
48
49 hwnd = CreateWindow (szAppName, TEXT ("Checker4 Mouse Hit-Test Demo"),
50 WS_OVERLAPPEDWINDOW,
51 CW_USEDEFAULT, CW_USEDEFAULT,
52 CW_USEDEFAULT, CW_USEDEFAULT,
53 NULL, NULL, hInstance, NULL) ;
54
55 ShowWindow (hwnd, iCmdShow) ;
56 UpdateWindow (hwnd) ;
57
58 while (GetMessage (&msg, NULL, 0, 0))
59 {
60 TranslateMessage (&msg) ;
61 DispatchMessage (&msg) ;
62 }
63 return msg.wParam ;
64 }
65
66 LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
67 {
68 static HWND hwndChild[DIVISIONS][DIVISIONS] ;
69 int cxBlock, cyBlock, x, y ;
70
71 switch (message)
72 {
73 case WM_CREATE :
74 for (x = 0 ; x < DIVISIONS ; x++)
75 for (y = 0 ; y < DIVISIONS ; y++)
76 hwndChild[x][y] = CreateWindow (szChildClass, NULL,
77 WS_CHILDWINDOW | WS_VISIBLE,
78 0, 0, 0, 0,
79 hwnd, (HMENU) (y << 8 | x),
80 (HINSTANCE) GetWindowLong (hwnd, GWL_HINSTANCE),
81 NULL) ;
82 return 0 ;
83
84 case WM_SIZE :
85 cxBlock = LOWORD (lParam) / DIVISIONS ;
86 cyBlock = HIWORD (lParam) / DIVISIONS ;
87
88 for (x = 0 ; x < DIVISIONS ; x++)
89 for (y = 0 ; y < DIVISIONS ; y++)
90 MoveWindow (hwndChild[x][y],
91 x * cxBlock, y * cyBlock,
92 cxBlock, cyBlock, TRUE) ;
93 return 0 ;
94
95 case WM_LBUTTONDOWN :
96 MessageBeep (0) ;
97 return 0 ;
98
99 // On set-focus message, set focus to child window
100
101 case WM_SETFOCUS:
102 SetFocus (GetDlgItem (hwnd, idFocus)) ;
103 return 0 ;
104
105 // On key-down message, possibly change the focus window
106
107 case WM_KEYDOWN:
108 x = idFocus & 0xFF ;
109 y = idFocus >> 8 ;
110
111 switch (wParam)
112 {
113 case VK_UP: y-- ; break ;
114 case VK_DOWN: y++ ; break ;
115 case VK_LEFT: x-- ; break ;
116 case VK_RIGHT: x++ ; break ;
117 case VK_HOME: x = y = 0 ; break ;
118 case VK_END: x = y = DIVISIONS - 1 ; break ;
119 default: return 0 ;
120 }
121
122 x = (x + DIVISIONS) % DIVISIONS ;
123 y = (y + DIVISIONS) % DIVISIONS ;
124
125 idFocus = y << 8 | x ;
126
127 SetFocus (GetDlgItem (hwnd, idFocus)) ;
128 return 0 ;
129
130 case WM_DESTROY :
131 PostQuitMessage (0) ;
132 return 0 ;
133 }
134 return DefWindowProc (hwnd, message, wParam, lParam) ;
135 }
136
137 LRESULT CALLBACK ChildWndProc (HWND hwnd, UINT message,
138 WPARAM wParam, LPARAM lParam)
139 {
140 HDC hdc ;
141 PAINTSTRUCT ps ;
142 RECT rect ;
143
144 switch (message)
145 {
146 case WM_CREATE :
147 SetWindowLong (hwnd, 0, 0) ; // on/off flag
148 return 0 ;
149
150 case WM_KEYDOWN:
151 // Send most key presses to the parent window
152
153 if (wParam != VK_RETURN && wParam != VK_SPACE)
154 {
155 SendMessage (GetParent (hwnd), message, wParam, lParam) ;
156 return 0 ;
157 }
158 // For Return and Space, fall through to toggle the square
159
160 case WM_LBUTTONDOWN :
161 SetWindowLong (hwnd, 0, 1 ^ GetWindowLong (hwnd, 0)) ;
162 SetFocus (hwnd) ;
163 InvalidateRect (hwnd, NULL, FALSE) ;
164 return 0 ;
165
166 // For focus messages, invalidate the window for repaint
167
168 case WM_SETFOCUS:
169 idFocus = GetWindowLong (hwnd, GWL_ID) ;
170
171 // Fall through
172
173 case WM_KILLFOCUS:
174 InvalidateRect (hwnd, NULL, TRUE) ;
175 return 0 ;
176
177 case WM_PAINT :
178 hdc = BeginPaint (hwnd, &ps) ;
179
180 GetClientRect (hwnd, &rect) ;
181 Rectangle (hdc, 0, 0, rect.right, rect.bottom) ;
182
183 // Draw the "x" mark
184
185 if (GetWindowLong (hwnd, 0))
186 {
187 MoveToEx (hdc, 0, 0, NULL) ;
188 LineTo (hdc, rect.right, rect.bottom) ;
189 MoveToEx (hdc, 0, rect.bottom, NULL) ;
190 LineTo (hdc, rect.right, 0) ;
191 }
192
193 // Draw the "focus" rectangle
194
195 if (hwnd == GetFocus ())
196 {
197 rect.left += rect.right / 10 ;
198 rect.right -= rect.left ;
199 rect.top += rect.bottom / 10 ;
200 rect.bottom -= rect.top ;
201
202 SelectObject (hdc, GetStockObject (NULL_BRUSH)) ;
203 SelectObject (hdc, CreatePen (PS_DASH, 0, 0)) ;
204 Rectangle (hdc, rect.left, rect.top, rect.right, rect.bottom) ;
205 DeleteObject(SelectObject (hdc, GetStockObject (BLACK_PEN))) ;
206 }
207
208 EndPaint (hwnd, &ps) ;
209 return 0 ;
210 }
211 return DefWindowProc (hwnd, message, wParam, lParam) ;
212 }