我是VC ++的新手,现在已经有几次了,这是第三个即使在成功构建后也不提供输出的程序。
#include <AFXWIN.H>
#include <math.h>
#define PI 3.1415926
#define SEGMENTS 500
class CMyApp : public CWinApp {
public:
virtual BOOL InitInstance();
};
class CMainWindow : public CFrameWnd
{
public:
CMainWindow();
protected:
afx_msg void OnPaint();
afx_msg void OnLButtonDown(UINT, CPoint);
DECLARE_MESSAGE_MAP();
};
CMyApp myAPP;
BOOL CMyApp::InitInstance() {
m_pMainWnd = new CMainWindow;
m_pMainWnd->ShowWindow(SW_MAXIMIZE);
m_pMainWnd->UpdateWindow();
return TRUE;
}
BEGIN_MESSAGE_MAP (CMainWindow, CFrameWnd)
ON_WM_PAINT ()
END_MESSAGE_MAP ()
CMainWindow::CMainWindow() {
Create(NULL,"The Hello Application",WS_OVERLAPPEDWINDOW);
}
void CMainWindow::OnPaint() {
CRect rect;
int nWidth = rect.Width();
int nHeight = rect.Height();
CPaintDC dc (this);
CPoint aPoint[SEGMENTS];
for (int i =0; i < SEGMENTS; i++){
aPoint[i].x = ((i*nWidth)/SEGMENTS );
aPoint[i].y= (int)((nHeight/2)* (1-(sin((2*PI*i)/SEGMENTS))));
}
dc.Polyline(aPoint, SEGMENTS);
UpdateData(false);
}
上面的程序应该给出正弦曲线作为输出,除了我得到一个空白窗口。我不知道为什么会这样。如果有帮助,我使用的是VC ++ 6.0