C++: accessing private fields and function from main

I've programmed only in Java in my career and started using C++ since 10 days, so this question may seem strange to many of you.
I have defined the structure of a class in a header file:

    #include "ros/ros.h"
    #include "nav_msgs/Odometry.h"
    #include "geometry_msgs/Pose.h"
    #include "geometry_msgs/Point.h"

    #include "stdio.h"
    #include "sensor_msgs/LaserScan.h"
    #include "list"
    #include "vector"
    #include "scan_node.h"
    #include "odom_node.h"
    #include "coord.h"

    class stage_listener{
    public:

        stage_listener();

    private:
        std::list odom_list;
        std::list scan_list;
        std::list corners_list;

        std::list polar2cart(std::vector, float, float, float, float);
        void addOdomNode (const nav_msgs::Odometry);
        void addScanNode (const sensor_msgs::LaserScan);

        void extractCorners(std::vector, float, float, float, float);
        int distance (float, float, float, float, float);
        void nodes2text(std::vector, std::vector);
        int numOdom();
        int numScan();
    };  

In the associated .cpp file, I wrote a main:

    int main(int argc, char **argv){
            char buffer [1024];
            while(1){
                int i = fscanf(stdin,"%s",buffer);

                if(strcmp("exit",buffer) == 0)
                    exit(0);


                else if(strcmp("num_nodes",buffer) == 0){
                    ROS_INFO("Odometry nodes: %i\nScan nodes: %i",numOdom(),numScan());
                }

                else{}
            }

    }

The ROS_INFO function is part of Willow Garage's ROS and you can intend it like a normal printf, taking exactly arguments in the same form.
On compiling code, I get the following:

/home/ubisum/fuerte_workspace/beginner/src/stage_listener.cpp: In function ‘int main(int, char**)’:
/home/ubisum/fuerte_workspace/beginner/src/stage_listener.cpp:223:5: error: ‘numOdom’ was not declared in this scope
/home/ubisum/fuerte_workspace/beginner/src/stage_listener.cpp:223:5: error: ‘numScan’ was not declared in this scope

Do you know the cause of the errors? In Java, you can access private fields/functions, so I can't understand the reason why in C++ it's not possible.