#include <windows.h>

int WINAPI WinMain(	HINSTANCE hInstance,
					HINSTANCE hPrevInstance,
					LPTSTR    lpCmdLine,
					int       nCmdShow)
{
	DEVMODE dm={{0},0,0,sizeof(DEVMODE),0,DM_DISPLAYQUERYORIENTATION};

	int r=ChangeDisplaySettingsEx(NULL,&dm,NULL,CDS_TEST,0);
	if((r==DISP_CHANGE_SUCCESSFUL) && (dm.dmDisplayOrientation!=DMDO_0))
	{
		DWORD dwSupported = dm.dmDisplayOrientation;
		dm.dmFields=DM_DISPLAYORIENTATION;
		r=ChangeDisplaySettingsEx(NULL,&dm,NULL,CDS_TEST,0);

		if(dm.dmDisplayOrientation==DMDO_0)
			dm.dmDisplayOrientation=DMDO_90;
		else
		{
			dm.dmDisplayOrientation*=2;
		}
		while(dm.dmDisplayOrientation && !(dm.dmDisplayOrientation & dwSupported))
		{
			dm.dmDisplayOrientation*=2;
			dm.dmDisplayOrientation%=8;
		}
		r=ChangeDisplaySettingsEx(NULL,&dm,NULL,CDS_RESET,0);
	}
	else 
		MessageBox(NULL,L"Screen Rotation is not supported.",NULL,0);

	return 0;
}