请使用c语言帮我实现DDCCI通信的代码，要包括DDCCI协议的内容

DDC/CI（Display Data Channel Command Interface）是一种用于电脑和显示器之间通信的协议，它可以通过VGA、DVI、HDMI等接口传输数据。以下是使用C语言实现DDC/CI通信的代码示例：

#include <windows.h>
#include <stdio.h>

#define DDC1_CMD_GET_VCP_FEATURE 0x01
#define DDC1_CMD_SET_VCP_FEATURE 0x02

void ddc1_get_vcp_feature(HANDLE hMonitor, BYTE vcpCode, BYTE *vcpResponse)
{
    BYTE inputBuffer[128];
    BYTE outputBuffer[128];
    DWORD inputBufferSize = 128;
    DWORD outputBufferSize = 128;
    DWORD bytesReturned;
    BOOL result;

    memset(inputBuffer, 0, sizeof(inputBuffer));
    memset(outputBuffer, 0, sizeof(outputBuffer));

    inputBuffer[0] = DDC1_CMD_GET_VCP_FEATURE;
    inputBuffer[1] = vcpCode;

    result = DeviceIoControl(hMonitor,
                             0xDC,
                             inputBuffer,
                             inputBufferSize,
                             outputBuffer,
                             outputBufferSize,
                             &bytesReturned,
                             NULL);

    if (result && (bytesReturned >= 3)) {
        *vcpResponse = outputBuffer[2];
    }
}

void ddc1_set_vcp_feature(HANDLE hMonitor, BYTE vcpCode, BYTE vcpValue)
{
    BYTE inputBuffer[128];
    DWORD inputBufferSize = 128;
    DWORD bytesReturned;
    BOOL result;

    memset(inputBuffer, 0, sizeof(inputBuffer));

    inputBuffer[0] = DDC1_CMD_SET_VCP_FEATURE;
    inputBuffer[1] = vcpCode;
    inputBuffer[2] = vcpValue;

    result = DeviceIoControl(hMonitor,
                             0xDC,
                             inputBuffer,
                             inputBufferSize,
                             NULL,
                             0,
                             &bytesReturned,
                             NULL);
}

int main()
{
    HANDLE hMonitor;
    DISPLAY_DEVICE displayDevice;
    DWORD monitorIndex = 0;
    BOOL result;
    BYTE vcpResponse = 0;

    memset(&displayDevice, 0, sizeof(displayDevice));
    displayDevice.cb = sizeof(displayDevice);

    while (EnumDisplayDevices(NULL, monitorIndex, &displayDevice, 0)) {
        if (displayDevice.StateFlags & DISPLAY_DEVICE_ATTACHED_TO_DESKTOP) {
            hMonitor = CreateFile(displayDevice.DeviceID,
                                  GENERIC_READ | GENERIC_WRITE,
                                  0,
                                  NULL,
                                  OPEN_EXISTING,
                                  0,
                                  NULL);

            if (hMonitor != INVALID_HANDLE_VALUE) {
                ddc1_get_vcp_feature(hMonitor, 0x10, &vcpResponse); // 获取亮度值
                printf("Monitor %d Brightness: %d\n", monitorIndex, vcpResponse);

                ddc1_set_vcp_feature(hMonitor, 0x10, 50); // 设置亮度值为50
                printf("Monitor %d Brightness has been set to 50\n", monitorIndex);

                CloseHandle(hMonitor);
            }
        }

        monitorIndex++;
    }

    return 0;
}

上述代码中，我们定义了两个函数：`ddc1_get_vcp_feature`和`ddc1_set_vcp_feature`，分别用于获取和设置DDC/CI的VCP功能值。其中，`inputBuffer`和`outputBuffer`分别用于输入和输出数据的缓存，`bytesReturned`用于记录实际读取或写入的字节数。

在`main`函数中，我们通过`EnumDisplayDevices`函数枚举所有连接到计算机的显示器，并对每个显示器进行亮度值的获取和设置操作。具体来说，我们使用`ddc1_get_vcp_feature`函数获取显示器的当前亮度值，并使用`ddc1_set_vcp_feature`函数将亮度值设置为50。

需要注意的是，DDC/CI通信需要管理员权限，因此在运行代码时需要以管理员身份运行。另外，不同的显示器支持的VCP功能值可能不同，具体的VCP功能值可以参考显示器的用户手册。