如何使用C++在Windows 7中将显示设置设置为EXTEND模式？

#include<iostream>
#include<Windows.h>

int main() {
    // 获取当前显示设置
    DEVMODE dm;
    ZeroMemory(&dm, sizeof(dm));
    dm.dmSize = sizeof(dm);
    EnumDisplaySettings(NULL, ENUM_CURRENT_SETTINGS, &dm);

    // 设置显示模式为EXTEND模式
    dm.dmPelsWidth = 1920;
    dm.dmPelsHeight = 1080;
    dm.dmDisplayFlags = DM_PELSWIDTH | DM_PELSHEIGHT;
    ChangeDisplaySettingsEx(NULL, &dm, NULL, CDS_UPDATEREGISTRY, NULL);

    // 刷新显示设置
    SendMessage(HWND_BROADCAST, WM_DISPLAYCHANGE, 0, 0);

    std::cout << "Display mode set to EXTEND mode."<< std::endl;
    return 0;
}