Topic not received? Try this

First of all, don't send it only once topic. Its second priority is ros::NodeHandle The problem of . Pay attention to the sending and receiving NodeHandle=n; Be consistent .

No, one is

ros::NodeHandle n;

The other is

ros::NodeHandle n("~");

It will lead to wrong topics for sending and receiving .

Want to know the details , You can refer to

ROS in NodeHandle nh And NodeHandle nh(“~“) difference _ Retro Blue blog -CSDN Blog