How to publish a topic on NAO (c++)?

edit

Hello,

It's my first time programming with ROS and NAO and I am trying to create a topic speech for NAO.

When I write this command in the console

rosrun proyects nao_test

the program run, but the NAO doesn't recieve the message that I send. This is my code and I think that something is missing

#include "ros/ros.h"
#include "std_msgs/String.h"

int main(int argc, char **argv)
{
        ros::init(argc, argv, "nao_test");
        ros::NodeHandle n;
        ros::Publisher speech_pub = n.advertise<std_msgs::String>("speech", 100);
        std_msgs::String str;
        str.data = "hello world";
        speech_pub.publish(str);

        return 0;
}

Thanks