How to use msgs in ros

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Hi dear I want to write a program that is tell me how many msgs that one node has published How can I write this program I wrot this program but it's not worked

#include "ros/ros.h"
#include "std_msgs/String.h"
int i=0;
  void chatterCallback(const std_msgs::String::ConstPtr& msg)
 {
  //ROS_INFO("I heard: [%s]", msg->data.c_str());
      i++;
 }

  int main(int argc, char **argv)
  {
      ros::init(argc, argv, "lisiner");
      ros::NodeHandle n;
      ros::Subscriber sub = n.subscribe("chater", 1000, chatterCallback);
      ros::Rate timeloop(5);
      while(ros::ok())
      {
          ROS_INFO("%d",i);
          timeloop.sleep();

      }

      return 0;
  }