帮我写一个c++使用GetWindowRect获取到窗口坐标后，在该窗口绘制一个边框作为显示

好的，以下是使用GetWindowRect获取窗口坐标并绘制边框的C代码：

#include <Windows.h>

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
    // 创建窗口
    WNDCLASS wc = { 0 };
    wc.lpfnWndProc = WndProc;
    wc.hInstance = hInstance;
    wc.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
    wc.lpszClassName = "MyWindowClass";
    RegisterClass(&wc);

    HWND hWnd = CreateWindow("MyWindowClass", "My Window", WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, CW_USEDEFAULT, 500, 500, NULL, NULL, hInstance, NULL);

    // 显示窗口
    ShowWindow(hWnd, nCmdShow);
    UpdateWindow(hWnd);

    // 消息循环
    MSG msg = { 0 };
    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }

    return (int)msg.wParam;
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)
    {
    case WM_PAINT:
    {
        // 获取窗口坐标
        RECT rect;
        GetWindowRect(hWnd, &rect);

        // 转换为客户区坐标
        POINT pt1 = { rect.left, rect.top };
        POINT pt2 = { rect.right, rect.bottom };
        ScreenToClient(hWnd, &pt1);
        ScreenToClient(hWnd, &pt2);
        rect.left = pt1.x;
        rect.top = pt1.y;
        rect.right = pt2.x;
        rect.bottom = pt2.y;

        // 绘制边框
        HDC hdc = GetDC(hWnd);
        HPEN hPen = CreatePen(PS_SOLID, 3, RGB(255, 0, 0));
        SelectObject(hdc, hPen);
        SelectObject(hdc, GetStockObject(NULL_BRUSH));
        Rectangle(hdc, rect.left, rect.top, rect.right, rect.bottom);
        DeleteObject(hPen);
        ReleaseDC(hWnd, hdc);
    }
    break;

    case WM_DESTROY:
        PostQuitMessage(0);
        break;

    default:
        return DefWindowProc(hWnd, message, wParam, lParam);
    }

    return 0;
}

这段代码会创建一个窗口，并在窗口的客户区绘制一个红色边框，边框的大小和位置与窗口相同。使用GetWindowRect获取窗口坐标后，需要将其转换为客户区坐标，然后使用Rectangle函数绘制矩形边框。