evarobot_gazebo using the topic /lidar in c++ node

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Hello, I have a problem reading values from the topic lidar in via a node:

Firstly I execute "roslaunch evarobot_gazebo evarobot.launch". After that I can read values by "rostopic echo /lidar -n1" command in another terminal, without a problem and it prints out 720 different distance values

But when it comes to my node it can get only 6 different distance values. And my node doesn't get effected by obstacles so it reads always as it's "inf" value.

I had also tried the code lines in "https://answers.ros.org/question/60239/how-to-extract-and-use-laser-data-from-scan-topic-in-ros-using-c/" but it gave compile error.

The problem documentation: "https://drive.google.com/open?id=1MHL9s7wWuKziYhN4nqojooWMplPTxX5z".

ulidar is the package in ~/catkin_ws/src/.

ps: I'm using ros-kinetic-desktop-full.

#include "ros/ros.h"
#include "geometry_msgs/Twist.h"
//#include "sensor_msgs/Range.h"
//#include "std_msgs/String.h" //old
#include <math.h>
#include "sensor_msgs/LaserScan.h"
#include "sensor_msgs/LaserEcho.h"


#define Uabs(x) ((x>0)?(x):(-x))

using namespace std;

struct vektor2d{
  double x;
  double y;
};
typedef struct vektor2d an2dVektor;

ros::Publisher theVelPub;
ros::Publisher theLaserEo;

void chtrCallBack(const sensor_msgs::LaserScan::ConstPtr& msgLsr);

int main(int argc, char ** argv)
{
    ros::init(argc,argv,"apf_lidar");
    ros::NodeHandle n;
    theVelPub = n.advertise<geometry_msgs::Twist>("/cmd_vel",10);
    /*theLaserEo = n.advertise<sensor_msgs::LaserEcho>("/lidar",10);
    sensor_msgs::LaserEcho lEcho;
    cout<<endl<<size:<<sizeof(lEcho.echoes)/sizeof(lEcho.echoes[0])<<endl;*/
    //theLaserEo.publish(lEcho);

    ros::Subscriber scanSub;
    scanSub=n.subscribe<sensor_msgs::LaserScan>("/lidar",1,chtrCallBack);
    int num=1;
    ros::Rate loop_rate(100);
    while(num--)
      loop_rate.sleep(), ros::spinOnce();
    return 0;
}
void chtrCallBack(const sensor_msgs::LaserScan::ConstPtr& msgLsr)
{
  cout<<endl<<"What's going on?"<<endl;
  int size=sizeof(msgLsr->ranges)/sizeof(msgLsr->ranges[0]);
  cout<<"Number of elements of array ranges:"<<size<<endl;
  while(size--)
    cout<<"ranges["<<size<<"]: "<<msgLsr->ranges[size]<<endl;
  cout<<"End of the CallBack"<<endl;
}

gives the output:

What's going on?
Number of elements of array ranges:6
ranges[5]: inf
ranges[4]: inf
ranges[3]: inf
ranges[2]: inf
ranges[1]: inf
ranges[0]: inf
End of the CallBack

Much obliged...