#include <windows.h>
#include <TCHAR.H>
LRESULT CALLBACK WndProc(HWND hwnd, UINT iMsg,
    WPARAM wParam, LPARAM lParam);
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
    LPSTR lpszCmdLine, int nCmdShow)
{
    HWND     hwnd;
    MSG      msg;
    WNDCLASS WndClass;
    WndClass.style = CS_HREDRAW | CS_VREDRAW;
    WndClass.lpfnWndProc = WndProc;
    WndClass.cbClsExtra = 0;
    WndClass.cbWndExtra = 0;
    WndClass.hInstance = hInstance;
    WndClass.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    WndClass.hCursor = LoadCursor(NULL, IDC_ARROW);
    WndClass.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
    WndClass.lpszMenuName = NULL;
    WndClass.lpszClassName = _T("Window Class Name");
    RegisterClass(&WndClass);
    hwnd = CreateWindow(_T("Window Class Name"),
        _T("윈도우프로그래밍_과제_20141825_한창기-2"),
        WS_OVERLAPPEDWINDOW,
        0,
        0,
        1000,
        800,
        NULL,
        NULL,
        hInstance,
        NULL
    );
    ShowWindow(hwnd, nCmdShow);
    UpdateWindow(hwnd);
    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return (int)msg.wParam;
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT iMsg,
    WPARAM wParam, LPARAM lParam)
{
    HDC hdc;
    PAINTSTRUCT ps;
    RECT rect = { 30,30,500,500 };
    static TCHAR str[100];
    static int count;
    switch (iMsg)
    {
    case WM_PAINT:
        hdc = BeginPaint(hwnd, &ps);
        DrawText(hdc, str, _tcslen(str), &rect, DT_LEFT | DT_BOTTOM|DT_WORDBREAK);
        EndPaint(hwnd, &ps);
        break;
    case WM_CHAR:
        hdc = GetDC(hwnd);
        if (wParam == VK_BACK)
        {
            if (count <= 0);
            else if (str[--count] == VK_RETURN) str[count--] = NULL; // 개행문자이면 한번 더 삭제
        }
        else if (count >= 99); // 넘어가는거 방지
        else
        {
            if (_tcslen(str) <= 0) str[count++] = wParam;
            else
            {
                for (int i = _tcslen(str); 0 <= i; i--) // 끝에서 한글자씩 땡겨서 맨 마지막 str[0]에 새로운 문자를 집어넣음
                {
                    str[i + 1] = str[i];
                }
                str[0] = wParam;
                count++;
            }
        }
        str[count] = NULL;
        InvalidateRgn(hwnd, NULL, TRUE);
        ReleaseDC(hwnd, hdc);
        break;
    case WM_CREATE:
        count = 0;
        break;
    case WM_DESTROY:
        PostQuitMessage(0);
        break;
    }
    return DefWindowProc(hwnd, iMsg, wParam, lParam);
}