////radiobutton demo
#include <windows.h>
#define ID_BLUE 1
#define ID_YELLOW 2
#define ID_RED 3
int red, green,blue;
COLORREF bk_color;
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
WNDCLASSEX wc;
MSG msg;
wc.cbSize = sizeof(WNDCLASSEX);
wc.style = 0;
wc.lpfnWndProc = WndProc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
wc.lpszMenuName = NULL;
wc.lpszClassName = TEXT("myWindowClass");
wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
RegisterClassEx(&wc);
CreateWindowEx(WS_EX_CLIENTEDGE, TEXT("myWindowClass"), TEXT("Radio Button Demo"), WS_VISIBLE | WS_OVERLAPPEDWINDOW, CW_USEDEFAULT, CW_USEDEFAULT, 700, 200, NULL, NULL, hInstance, NULL);
while (GetMessage(&msg, NULL, 0, 0) > 0)
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
return msg.wParam;
}


LRESULT CALLBACK WndProc(HWND hwnd, UINT msg,
WPARAM wParam, LPARAM lParam) {
PAINTSTRUCT ps;
HBRUSH hBrush;
switch(msg) {
case WM_CREATE:
bk_color = RGB(255, 255, 255);
/*create grouping box and associated buttons.*/
CreateWindow(TEXT("button"), TEXT("Choose colour"), WS_CHILD | WS_VISIBLE | BS_GROUPBOX,50,25,300,70, hwnd, (HMENU) 0, NULL, NULL);
CreateWindow(TEXT("button"), TEXT("Blue"),WS_CHILD | WS_VISIBLE | BS_AUTORADIOBUTTON,70,50,75,30, hwnd, (HMENU) ID_BLUE ,NULL, NULL);
CreateWindow(TEXT("button"), TEXT("Yellow"),WS_CHILD | WS_VISIBLE | BS_AUTORADIOBUTTON,145,50,85,30, hwnd, (HMENU) ID_YELLOW , NULL, NULL);
CreateWindow(TEXT("button"), TEXT("Red"),WS_CHILD | WS_VISIBLE | BS_AUTORADIOBUTTON,230,50,75,30, hwnd, (HMENU) ID_RED ,NULL, NULL);
break;
case WM_COMMAND:
/*responds to button click by setting variable bk_color to value of colour associated with radio button */
if (HIWORD(wParam) == BN_CLICKED) {
switch (LOWORD(wParam)) {
case ID_BLUE:
bk_color = RGB(0, 76, 255);
break;
case ID_YELLOW:
bk_color = RGB(255, 255, 0);
break;
case ID_RED:
bk_color = RGB(255, 0, 0);
break;
}
HDC hdc;
hdc=GetDC(hwnd);
SetBkColor(hdc,bk_color);
RECT theRect;
GetClientRect(hwnd, &theRect);
InvalidateRect(hwnd,&theRect,TRUE);
ReleaseDC(hwnd,hdc);
DeleteDC(hdc);
}
break;
case WM_PAINT:
/*set background of window to colour selected by radiobutton selection ie red blue or yellow*/
HDC hdc;
hdc = BeginPaint(hwnd, &ps);
hBrush = CreateSolidBrush(bk_color);
RECT theRect;
GetClientRect(hwnd, &theRect);
FillRect(hdc, &theRect, hBrush);
DeleteObject(hBrush);
EndPaint(hwnd, &ps);
ReleaseDC(hwnd,hdc);
DeleteDC(hdc);
break;
case WM_DESTROY:
PostQuitMessage(0);
break;
}
return DefWindowProc(hwnd, msg, wParam, lParam);
}