error getMD5Sum in customized message type

edit

Hi everyone, I am a newbie trying to create a customized message type but it always ends up with this error. I will appreciate greatly if someone can help out. I spent hours on this and don't know where is the error.

error msg is at the end.

Photos of my simple files are posted in this link: https://imgur.com/a/E48bRef

Edit: Here is everything in text:

Cmake.txt:

cmake_minimum_required(VERSION 2.8.3)
project(hola)
find_package(catkin REQUIRED COMPONENTS
  roscpp
  std_msgs
  sensor_msgs
  message_generation
)

add_message_files(
  FILES
  ParsedPointCloud.msg
 )

generate_messages(
   DEPENDENCIES
   sensor_msgs
   std_msgs
)

catkin_package(
INCLUDE_DIRS include/${PROJECT_NAME}/
CATKIN_DEPENDS roscpp sensor_msgs message_runtime std_msgs
)

include_directories(
  include
  ${catkin_INCLUDE_DIRS}
)

add_executable(hola src/getdata.cpp)
target_link_libraries(hola ${catkin_LIBRARIES})

my header file in hola/include/ParsedPointCloud.h:

#include <vector>

namespace hola{

    class PPC{
    public:
        std::vector<float> dist;
        std::vector<float> angle;
    };
}

ParsedPointCloud.msg in msg directory:

float32[] dist  
float32[] angle

Package.xml:

<?xml version="1.0"?>
<package format="2">
  <name>hola</name>
  <version>0.0.0</version>
  <description>The hola package</description>
  <maintainer email="richard@todo.todo">richard</maintainer>
  <license>TODO</license>

  <buildtool_depend>catkin</buildtool_depend>
  <build_depend>roscpp</build_depend>
  <build_depend>message_generation</build_depend>
  <build_depend>sensor_msgs</build_depend>
  <build_depend>std_msgs</build_depend>
  <build_export_depend>roscpp</build_export_depend>
  <build_export_depend>std_msgs</build_export_depend>
  <build_export_depend>sensor_msgs</build_export_depend>
  <build_export_depend>message_runtime</build_export_depend>
  <exec_depend>roscpp</exec_depend>
  <exec_depend>sensor_msgs</exec_depend>
  <exec_depend>std_msgs</exec_depend>
  <exec_depend>message_runtime</exec_depend>

  <!-- The export tag contains other, unspecified, tags -->
  <export>
    <!-- Other tools can request additional information be placed here -->

  </export>
</package>

Finally my code:

 #include <ros/ros.h> 
  #include <vector>
  #include <sensor_msgs/LaserScan.h>
  #include <hola/ParsedPointCloud.h>

  hola::PPC pc; 

  void parsefunc(const sensor_msgs::LaserScan &msg){
    float min = msg.range_min;
    float max = msg.range_max;

    for(int i = 0; i < 1081; i++){ //270*4+1 = 1081  #points on one plane.

        //limiting measurement to range_min and range_max
        float tempdist = min;
        if(msg.ranges[4*i] > max) tempdist = max;
        else if(msg.ranges[4*i] < max && msg.ranges[4*i] > min) tempdist = msg.ranges[4*i];

        pc.dist[i] = tempdist;
        pc.angle[i] = -135+(i*0.25);
    }
  }

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

    pc.dist.resize(1081);
    pc.angle.resize(1081);

    ros::init(argc,argv,"getdata");
    ros::NodeHandle nh;
    ros::Subscriber sub = nh.subscribe("scan",1000,&parsefunc);
    ros::Publisher pub = nh.advertise<hola::PPC>("parsedPC",1000);  

    while(ros::ok()){
        ros::spinOnce();
        pub.publish(pc);
    }
  }

Error message:

In file included from /opt/ros/melodic/include/ros/serialization.h:37:0,
                 from /opt/ros/melodic/include/ros/publisher.h:34,
                 from /opt/ros/melodic/include/ros/node_handle.h:32,
                 from /opt/ros/melodic/include/ros/ros.h:45,
                 from /home/richard/new_ws/src/hola/src/getdata.cpp:1:
/opt/ros/melodic/include/ros/message_traits.h: In instantiation of ‘static const char* ros::message_traits::MD5Sum<M>::value(const M&) [with M = hola::PPC]’:
/opt/ros/melodic/include/ros/message_traits.h:255:102:   required from ‘const char* ros::message_traits::md5sum(const M&) [with M = hola::PPC]’
/opt/ros/melodic/include/ros/publisher.h:112:7:   required from ‘void ros::Publisher::publish(const M&) const [with M = hola::PPC]’
/home/richard/new_ws/src/hola/src/getdata.cpp:36 ...