#include "ros/ros.h"

#include "std_msgs/String.h"


//回调函数，接收到话题后进入

void chatterCallback( const std_msgs::String::ConstPtr& msg  )

{

    ROS_INFO(  "heard:[%s]", msg->data.c_str() );

}

int main( int argc, char** argv  )

{

    ros::init(argc,argv,"listener");  //初始化一个名为listener的节点

    ros::NodeHandle n;

    ros::Subscriber sub = n.subscribe("chatter",1000,chatterCallback);    //订阅一个话题

    ros::spin();   //节点进入循环状态

    return 0;

}

#include "ros/ros.h"

#include "std_msgs/String.h"

#include <sstream>

int main(int argc, char **argv) {

  ros::init(argc, argv, "talker");

  ros::NodeHandle n;

  ros::Publisher chatter_pub = n.advertise<std_msgs::String>("chatter", 1000);   //发布一个话题

  ros::Rate loop_rate(10);   //设置循环的频率，10hz

  int count = 0;

  while (ros::ok()) {

    std_msgs::String msg;

    std::stringstream ss;

    ss << "helloworld" << count;

    msg.data = ss.str();

    chatter_pub.publish(msg);

    ros::spinOnce();

    loop_rate.sleep();

    ++count;

  }

  return 0;

}

add_executable(talker src/talker.cpp)

target_link_libraries(talker ${catkin_LIBRARIES})

add_dependencies(talker ${PROJECT_NAME}_generate_messages_cpp)

add_executable(listener src/listener.cpp)

target_link_libraries(listener ${catkin_LIBRARIES})

add_dependencies(listener ${PROJECT_NAME}_generate_messages_cpp)