ITRTCCloud

  Json::Value jsonObj;
  jsonObj["roomId"] = 102;
  jsonObj["userId"] = "userB";
  Json::FastWriter writer;
  std::string params = writer.write(jsonObj);
  trtc.ConnectOtherRoom(params.c_str());

  Json::Value jsonObj;
  jsonObj["strRoomId"] = "102";
  jsonObj["userId"] = "userB";
  Json::FastWriter writer;
  std::string params = writer.write(jsonObj);
  trtc.ConnectOtherRoom(params.c_str());

    //In the small room that needs interaction, enter the room as an anchor and push audio and video streams
    ITRTCCloud *mainCloud = getTRTCShareInstance();
    TRTCParams mainParams;
    //Fill your params
    mainParams.role = TRTCRoleAnchor;
    mainCloud->enterRoom(mainParams, TRTCAppSceneLIVE);
    //...
    mainCloud->startLocalAudio(TRTCAudioQualityDefault);
    mainCloud->startLocalPreview(renderView);
    
    //In the large room that only needs to watch, enter the room as an audience and pull audio and video streams
    ITRTCCloud *subCloud = mainCloud->createSubCloud();
    TRTCParams subParams;
    //Fill your params
    subParams.role = TRTCRoleAudience;
    subCloud->enterRoom(subParams, TRTCAppSceneLIVE);
    //...
    subCloud->startRemoteView(userId, TRTCVideoStreamTypeBig, renderView);
    //...
    //Exit from new room and release it.
    subCloud->exitRoom();
    mainCloud->destroySubCloud(subCloud);

{
  "roomId":102,
  "userId":"userC",
  "muteAudio":false,
  "muteVideo":true,
  "muteSubStream":false
}

{
  "strRoomId":"102",
  "userId":"userC",
  "muteAudio":false,
  "muteVideo":true,
  "muteSubStream":false
}