CosResult GetObject(const GetObjectByFileReq& request, GetObjectByFileResp* response);

qcloud_cos::CosConfig config("./config.json");
qcloud_cos::CosAPI cos(config);
std::string bucket_name = "examplebucket-1250000000";

qcloud_cos::GetObjectByFileReq req(bucket_name, object_name, local_file);
// Scale an image to 50% of its original width and height
req.AddParam("imageMogr2/thumbnail/!50p", "");
qcloud_cos::GetObjectByFileResp resp;
qcloud_cos::CosResult result = cos.GetObject(req, &resp);
if (result.IsSucc()) {
   // The call is successful. You can call the `resp` member functions to get the return content.
} else {
   // The call failed. You can call the `result` member functions to get the error information.
}