Refactoring basic ROS code into object-oriented one

edit

I was trying to refactor the existing basic ROS talker code into somewhat that of using OO paradigm. By the way, I am not a good object-oriented programmer but willing to practice a lot and apply in any projects that I am involved. Here I provide the code and there are currently 2 problems I am having. They are:

1. Problem with the PointCloud constructor. I got an error of "extra qualification ‘PointCloud::’ on member ‘PointCloud’".
2. I'm confused the way I should use loop_rate().

Hopefully, someone who are very good in OO programming can help or improve this little thing..The code:

#include "ros/ros.h"
#include "std_msgs/String.h"
#include <sstream>


class PointCloud
{

private:
    int count;
    PointCloud();
    ros::NodeHandle n;
    ros::Publisher chatter_pub;
//  ros::Rate loop_rate(int);
    std_msgs::String msg;
    std::stringstream ss;

public:

PointCloud::PointCloud()
{
    chatter_pub = n.advertise<std_msgs::String>("chatter", 1000);
}

void display();
};

void PointCloud::display()
{
//      loop_rate(10);

    count = 0;
    while (ros::ok())
    {
        ss << "hello world " << count;
        msg.data = ss.str();

        ROS_INFO("%s", msg.data.c_str());

        chatter_pub.publish(msg);

        ros::spinOnce();

//          loop_rate.sleep();
        ++count;
    }
 }
int main(int argc, char **argv)
{
    ros::init(argc, argv, "talker");
    PointCloud pointCloud;
    ROS_INFO("Node started");
    ros::spin(); 
    ROS_INFO("Node finished");

   return 0;
}

The modified code:

#include "ros/ros.h"
#include "std_msgs/String.h"
#include <sstream>


class PointCloud
{
private:
    ros::NodeHandle n;
    ros::Publisher chatter_pub;

    int count;

public:
    PointCloud();
    void display();
};

    PointCloud::PointCloud()
    {
        chatter_pub = n.advertise<std_msgs::String>("chatter", 1000);
            count = 0;
    }

    void PointCloud::display()
    {
        std_msgs::String msg;
        std::stringstream ss;
        ss << "hello world " << count;
        msg.data = ss.str();
        ROS_INFO("%s", msg.data.c_str());
        chatter_pub.publish(msg);
        ++count;
    }

int main(int argc, char **argv)
{
    ros::init(argc, argv, "talker");
    PointCloud pointCloud;
    ROS_INFO("Node started");

    ros::Rate loop_rate(10);

    while (ros::ok())
    {
        ros::spinOnce();
        pointCloud.display();
        loop_rate.sleep();
    }

    ROS_INFO("Node finished");

  return 0;
}