一般模式

学过C++类的都知道C++的类该怎么使用，对于ROS来说也是同样的做法。
在头文件中定义类：

定义私有和共有成员变量
定义类的构造函数
定义私有和共有成员函数

单独编写一个实现文件

包含头文件
实现成员函数的原型

头文件

#ifndef EXAMPLE_ROS_CLASS_H_
#define EXAMPLE_ROS_CLASS_H_

#include <math.h>
#include <stdlib.h>
#include <string>
#include <vector>
#include <ros/ros.h>
#include <std_msgs/Bool.h>
#include <std_msgs/Float32.h>
#include <std_srvs/Trigger.h>

class ExampleRosClass
{
private:
ExampleRosClass(ros::NodeHandle* nodehandle);
public:
ros::NodeHandle n;
ros::Publisher minimal_publisher;
ros::Subscriber minimal_subscriber;
ros::ServiceServer minimal_service;
double val_from_subscriber;
double val_to_remember;
void initializePublishers();
void initializeSubscribers();
void initializeServices();
void subscriberCallback(const std_msgs::Float32& message_holder);
bool serviceCallback(std_srvs::TriggerRequest& request,std_srvs::TriggerResponse& response);
};
#endif

#实现文件

#include <example_ros_class.h>
ExampleRosClass::ExampleRosClass(ros::NodeHandle* nodehandle):n(*nodehandle)
{
	ROS_INFO("in class constructor of ExampleRosClass");
	initializePublishers();
	initializeSubscribers();
	initializeServices();
	val_to_remember=0.0;
}
void ExampleRosClass::initializePublishers()
{
	ROS_INFO("Initializing Publishers");
	minimal_publisher=n.advertise<std_msgs::Float32>("example_class_output_topic",1,true);
}
void ExampleRosClass::initializeSubscribers()
{
	ROS_INFO("Initializing Subscribers");
	minimal_subscriber=n.subscribe("example_class_input_topic",1,&ExampleRosClass::subscriberCallback,this);
}
void ExampleRosClass::initializeServices()
{
	ROS_INFO("Initializing Services");
	minimal_service=n.advertiseService("example_minimal_service",&ExampleRosClass::serviceCallback,this);
}
void ExampleRosClass::subscriberCallback(const std_msgs::Float32& message_holder)
{
	val_from_subscriber=message_holder.data;
	ROS_INFO("myCallback activated: received value %f",val_from_subscriber);
	std_msgs::Float32 output_msg;
	val_to_remember += val_from_subscriber;
	output_msg.data=val_to_remember;
	minimal_publisher.publish(output_msg);
}
bool ExampleRosClass::serviceCallback(std_srvs::TriggerRequest& request,std_srvs::TriggerResponse& response)
{
	ROS_INFO("service callback activated");
	response.success = true;
	response.message = "here is a response string";
	return true;
}
int main(int argc,char **argv)
{
	ros::init(argc,argv,"exampleRosClass");
	ros::NodeHandle nh;
	ROS_INFO("main:instantiating an objecy of type ExampleRosClass");
	ExampleRosClass exampleRosClass(&nh);
	ROS_INFO("main: going into spin");
	ros::spin();
	return 0;
}