타이머를 이용한 시계

#include<windows.h>

LRESULT CALLBACK WndProc(HWND,UINT,WPARAM,LPARAM);
HINSTANCE g_hInst;
LPCTSTR lpszClass=TEXT("My Timer");

// WinMain 시작
int APIENTRY WinMain(HINSTANCE hInstance,HINSTANCE hPrevlnstance, LPSTR lpszCmdParam, int nCmdShow)
{
 HWND hWnd;
 MSG Message;
 WNDCLASS WndClass;
 g_hInst=hInstance;

 // 1. 윈도우 속성값 등록
 WndClass.cbClsExtra=0;
 WndClass.cbWndExtra=0;
 WndClass.hbrBackground=(HBRUSH)GetStockObject(WHITE_BRUSH);
 WndClass.hCursor=LoadCursor(NULL,IDC_ARROW);
 WndClass.hIcon=LoadIcon(NULL,IDI_APPLICATION);
 WndClass.hInstance=hInstance;
 WndClass.lpfnWndProc=WndProc;
 WndClass.lpszClassName=lpszClass;
 WndClass.lpszMenuName=NULL;
 WndClass.style=CS_HREDRAW|CS_VREDRAW;
 RegisterClass(&WndClass); // 주소에 Write

 // 2. 윈도우 생성
 hWnd=CreateWindow(lpszClass,lpszClass,WS_OVERLAPPEDWINDOW
  ,CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,CW_USEDEFAULT,NULL,
  (HMENU)NULL,hInstance,NULL);

 ShowWindow(hWnd,nCmdShow);  // 화면에 뿌려줌

 // 3. 메세지 처리 (무한반복)
 while(GetMessage(&Message,NULL,0,0))
 {
  TranslateMessage(&Message);
  DispatchMessage(&Message);
 }
 return (int)Message.wParam;
}

LRESULT CALLBACK WndProc(HWND hWnd,UINT iMessage,WPARAM wParam,LPARAM IParam)
{
 HDC hdc;
 PAINTSTRUCT ps;
 SYSTEMTIME st;
 static TCHAR sTime[128];
 static RECT rt = { 100, 100, 400, 120};

 switch(iMessage)
 {
 case WM_CREATE:
  SetTimer(hWnd, 1, 1000, NULL);
  return 0;
 
 case WM_TIMER:
  GetLocalTime(&st);
  wsprintf(sTime, TEXT("지금시간은 %d : %d : %d 입니다"), st.wHour, st.wMinute, st.wSecond);
 InvalidateRect(hWnd, &rt, TRUE);
 return 0;
 
 case WM_PAINT:
  hdc = BeginPaint(hWnd, &ps);
  TextOut(hdc, 100, 100, sTime, lstrlen(sTime)); 
  EndPaint(hWnd, &ps);
  return 0;
 
 case WM_DESTROY:
  KillTimer(hWnd,1);
  PostQuitMessage(0);
  return 0;

 }

 return(DefWindowProc(hWnd,iMessage,wParam,IParam));
}