1.14

#include <windows.h>
 
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
HINSTANCE g_hInst;
HWND hWndMain;
LPCTSTR lpszClass = TEXT("Class");
//char *lpszClass ="Class";//윗소스와 동일
int APIENTRY WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance
    , LPSTR lpszCmdParam, 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;
}
int px[1000], py[1000];
int iCount;
 
LRESULT CALLBACK WndProc(HWND hWnd, UINT iMessage, WPARAM wParam, LPARAM lParam)
{//WndProc: window procedure=꼬리 똥그라미ㅋㅋㅋ
    HDC hdc;
    PAINTSTRUCT ps;
    int x=0, y=0;
 
    switch (iMessage) {
    case WM_CREATE:
        hWndMain = hWnd;
        return 0;    
    case WM_LBUTTONDOWN:
        hdc = GetDC(hWnd);
        px[iCount]= x = LOWORD(lParam); //사용자가 누른 점의 개수가 저장됨
        py[iCount] = y = HIWORD(lParam);
 
        //Rectangle(hdc, 10, 10, 30, 30);
        //단위는 px(픽셀) 10,10에 점 + 30,30에 점 그래서 한변의 길이 20
        //지정된 지점으로부터 네모를 만드는 것
        iCount++;
        Rectangle(hdc, x-20, y-20, x+20, y+20);
        //커서 클릭한 지점으로부터 네모를 만드는 것
        return 0;
 
    case WM_PAINT://다시그려야 한다고 말함 //창에 점을 막 찍고 내렸다가 올리면 다시 새 창
        hdc = BeginPaint(hWnd, &ps);
        for (int i = 0; i < iCount; i++)
        {
            Rectangle(hdc, px[i] - 20, py[i] - 20,
                            px[i] + 20, py[i] + 20);
        }
        Rectangle(hdc, x - 20, y - 20, x + 20, y + 20);//지정된 지점으로부터 네모를 만든게 그대로 있슴
        EndPaint(hWnd, &ps);
        return 0;
    case WM_DESTROY:
        PostQuitMessage(0);
        return 0;
    }
    return(DefWindowProc(hWnd, iMessage, wParam, lParam));
}