구조

#include <Windows.h>
 
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
HINSTANCE g_hInst;
HWND hWndMain;
LPCTSTR lpszClass = TEXT("Class");
 
int APIENTRY WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, 
                        LPSTR lpszCmbParam, int nCmdShow)
{
    HWND hWnd;
    MSG Message;
    WNDCLASS WndClass;
    g_hInst = hInstance;
 
    WndClass.cbClsExtra = 0;
    WndClass.cbWndExtra = 0;
    WndClass.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
    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);
 
    hWnd = CreateWindow(lpszClass, lpszClass, WS_OVERLAPPEDWINDOW,
                        CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT,
                        NULL, (HMENU)NULL, hInstance, NULL);
 
    ShowWindow(hWnd, nCmdShow);
 
    while (GetMessage(&Message, NULL, 0, 0)) {
        TranslateMessage(&Message);
        DispatchMessage(&Message);
    }
 
    return (int)Message.wParam;
}
 
LRESULT CALLBACK WndProc(HWND hWnd, UINT iMessage, WPARAM wParam, LPARAM lParam)
{
    HDC hdc;
    PAINTSTRUCT ps;
 
    switch (iMessage) {
    case WM_CREATE:
        hWndMain = hWnd;
        return 0;
    case WM_PAINT:
        hdc = BeginPaint(hWnd, &ps);
        EndPaint(hWnd, &ps);
        return 0;
    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;
    }
 
    return (DefWindowProc(hWnd, iMessage, wParam, lParam));
}