jdumont0201

#include <ros/ros.h> 
  int main(int argc, char** argv) { 
  ros::init(argc, argv, "Hello, World");
  ros::NodeHandle nh; ROS_INFO("Hello, World!"); 
  ros::spinOnce(); return 0; 
}

jdumont0201

<launch> 
  <!-- ~/catkin_ws/src/my_package/launch/minimal.launch -->
  <node pkg="my_package" type="simple" name="HelloWorld"  output="screen"></node> 
</launch>

jdumont0201

#include  <ros/ros.h> 
int main(int argc, char** argv) {
    ros::init(argc, argv, "ObiWan");
    ros::NodeHandle nh;
    ros::Rate loop_rate(2); // We create a Rate object of 2Hz
    while (ros::ok()) { // Endless loop until Ctrl + C
        ROS_INFO("Hello, World!");
        ros::spinOnce();
        loop_rate.sleep(); // We sleep the needed time to maintain the Rate fixed above
    }

jdumont0201

#include <ros/ros.h>
#include <std_msgs/Int32.h>

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

    ros::init(argc, argv, "topic_publisher");
    ros::NodeHandle nh;
    
    ros::Publisher pub = nh.advertise&lt;std_msgs::Int32&gt;("counter", 1000);
    ros::Rate loop_rate(2);

jdumont0201

#include <ros/ros.h> 
#include <geometry_msgs/Twist.h> 
int main(int argc, char** argv) {
  ros::init(argc, argv, "topic_publisher"); ros::NodeHandle nh;

    ros::Publisher pub = nh.advertise("cmd_vel",1000);
    ros::Rate loop_rate(2);

    geometry_msgs::Twist twist;
    twist.linear.x=0.5;

jdumont0201

#include <ros/ros.h>
#include <std_msgs/Int32>

void counterCallback(const std_msgs::Int32::ConstPtr& msg)
{
  ROS_INFO("%d", msg->data);
}

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

jdumont0201

#include <ros/ros.h> 
#include <sensor_msgs/LaserScan.h>

void counterCallback(const sensor_msgs::LaserScan::ConstPtr& msg){
    ROS_INFO("LaserScan (val,angle)=(%f,%f", msg->range_min,msg->angle_min);
}
int main(int argc, char** argv) {
    ros::init(argc, argv, "topic_subscriber");
    ros::NodeHandle nh;
    ros::Subscriber sub = nh.subscribe("/kobuki/laser/scan", 1000, counterCallback);

jdumont0201

#include "ros/ros.h"
#include "gazebo_msgs/DeleteModel.h" 

int main(int argc, char **argv){
  ros::init(argc, argv, "service_client"); // Initialise a ROS node with the name service_client
  ros::NodeHandle nh;
  
  // Create the connection to the service /gazebo/delete_model
  ros::ServiceClient delete_model_service = nh.serviceClient<gazebo_msgs::DeleteModel>("/gazebo/delete_model");

jdumont0201

#include "ros/ros.h" #include "std_srvs/Empty.h" // Import the service message header file generated from the Empty.srv message

bool my_callback(std_srvs::Empty::Request  &req, std_srvs::Empty::Response &res){
//process some action
ROS_INFO("My_callback has been called");
  return true;
}

int main(int argc, char **argv){
  ros::init(argc, argv, "service_server");

jdumont0201

 find_package(catkin REQUIRED COMPONENTS roscpp std_msgs message_generation )

...

add_service_files(
  FILES
  MyCustomServiceMessage.srv
)

...