A、 ros::NodeHandlenh;ros::Publisherpub=nh.advertise("mytopic",std_msgs::Int32,10);
B、 ros::NodeHandlenh;ros::Publisherpub=nh.advertise<std_msgs::Int32>("mytopic",10);
C、 ros::Publisherpub("mytopic",std_msgs::Int32,10);
D、 ros::Publisher<std_msgs::Int32>pub("mytopic",10);