ros话题

subscribe.cpp

#include "ros/ros.h"
#include "std_msgs/Int32.h"
#include <sstream>
void chatterCallback(const std_msgs::Int32::ConstPtr& msg)
{
  ROS_INFO("I heard:[%d]",msg->data);

}
int main(int argc, char **argv)
{
  ros::init(argc, argv, "example_talker_msg");
  ros::NodeHandle n;
  ros::Subscriber sub = n.subscribe("third_pkg_topic", 1000,chatterCallback);
  ros::Rate loop_rate(10);
    ros::spin();
  return 0;

}

third_pkg.cpp:
#include "ros/ros.h"
#include "std_msgs/Int32.h"
#include <sstream>

int main(int argc, char **argv)
{
  ros::init(argc, argv, "example_talker_msg");
  ros::NodeHandle n;
  ros::Publisher pub = n.advertise<std_msgs::Int32>("third_pkg_topic", 1000);
  ros::Rate loop_rate(2);
  int count=0;
  while (ros::ok())
  {
    
    std_msgs::Int32 msg;
    //std::stringstream ss;
    //ss << "third_pkg" << count;
    msg.data=count;
    ROS_INFO("%d",msg.data);
   pub.publish(msg);
    ros::spinOnce();
    loop_rate.sleep();
    ++count;
  }
  return 0;

}