用C++windows窗口应用程序写一段代码，调试时显示封面界面，然后按下F1、F2、F3、F4、F5时，系统分别切换五张图片

好的，以下是一份简单的代码实现：

#include <Windows.h>

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

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
    // 创建窗口类
    WNDCLASSEX wc;
    wc.cbSize = sizeof(WNDCLASSEX);
    wc.style = CS_HREDRAW | CS_VREDRAW;
    wc.lpfnWndProc = WndProc;
    wc.cbClsExtra = 0;
    wc.cbWndExtra = 0;
    wc.hInstance = hInstance;
    wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wc.hCursor = LoadCursor(NULL, IDC_ARROW);
    wc.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
    wc.lpszMenuName = NULL;
    wc.lpszClassName = "MyWindowClass";
    wc.hIconSm = LoadIcon(NULL, IDI_APPLICATION);

    // 注册窗口类
    if (!RegisterClassEx(&wc))
    {
        MessageBox(NULL, "窗口类注册失败！", "错误", MB_ICONERROR | MB_OK);
        return 0;
    }

    // 创建窗口
    HWND hWnd = CreateWindowEx(
        WS_EX_CLIENTEDGE,
        "MyWindowClass",
        "图片切换程序",
        WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT, CW_USEDEFAULT, 600, 400,
        NULL, NULL, hInstance, NULL);

    if (hWnd == NULL)
    {
        MessageBox(NULL, "窗口创建失败！", "错误", MB_ICONERROR | MB_OK);
        return 0;
    }

    // 显示封面界面
    HDC hdc = GetDC(hWnd);
    HBITMAP hBmp = (HBITMAP)LoadImage(NULL, "cover.bmp", IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
    HDC hMemDC = CreateCompatibleDC(hdc);
    SelectObject(hMemDC, hBmp);
    BitBlt(hdc, 0, 0, 600, 400, hMemDC, 0, 0, SRCCOPY);
    DeleteDC(hMemDC);
    ReleaseDC(hWnd, hdc);

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

    // 消息循环
    MSG msg;
    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return (int)msg.wParam;
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
    static HBITMAP hBmps[5];
    static int idx = 0;

    switch (msg)
    {
    case WM_CREATE:
        // 加载五张图片
        hBmps[0] = (HBITMAP)LoadImage(NULL, "pic1.bmp", IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
        hBmps[1] = (HBITMAP)LoadImage(NULL, "pic2.bmp", IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
        hBmps[2] = (HBITMAP)LoadImage(NULL, "pic3.bmp", IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
        hBmps[3] = (HBITMAP)LoadImage(NULL, "pic4.bmp", IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
        hBmps[4] = (HBITMAP)LoadImage(NULL, "pic5.bmp", IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
        break;
    case WM_KEYDOWN:
        // 根据按键切换图片
        switch (wParam)
        {
        case VK_F1:
            idx = 0;
            break;
        case VK_F2:
            idx = 1;
            break;
        case VK_F3:
            idx = 2;
            break;
        case VK_F4:
            idx = 3;
            break;
        case VK_F5:
            idx = 4;
            break;
        default:
            break;
        }

        // 绘制图片
        HDC hdc = GetDC(hWnd);
        HDC hMemDC = CreateCompatibleDC(hdc);
        SelectObject(hMemDC, hBmps[idx]);
        BitBlt(hdc, 0, 0, 600, 400, hMemDC, 0, 0, SRCCOPY);
        DeleteDC(hMemDC);
        ReleaseDC(hWnd, hdc);
        break;
    case WM_DESTROY:
        // 释放图片资源
        for (int i = 0; i < 5; i++)
        {
            DeleteObject(hBmps[i]);
        }
        PostQuitMessage(0);
        break;
    default:
        return DefWindowProc(hWnd, msg, wParam, lParam);
    }
    return 0;
}

在该程序中，我们使用了 `LoadImage` 函数来加载图片资源，并且在窗口创建时显示了封面界面。在消息处理函数中，我们根据按键消息（即 `WM_KEYDOWN`）切换图片，并且使用 `BitBlt` 函数将图片绘制到窗口上。

请将上述代码保存为 `main.cpp` 文件，同时将 `cover.bmp`、`pic1.bmp`、`pic2.bmp`、`pic3.bmp`、`pic4.bmp`、`pic5.bmp` 这六个文件放在同一目录下。然后使用 Visual Studio 等 IDE 编译并运行该程序，即可看到效果。