calling service with ros::ServiceClient [closed]

edit

I posted the code and the error that i see when i do rosmake. someone can halp me for detecting the error?

#include <ros/ros.h>
#include "gazebo_msgs/SetModelState.h"

...

ros::ServiceClient client = n.serviceClient<gazebo_msgs::SetModelState>("/gazebo/set_model_state");
        gazebo_msgs::SetModelState setmodelstate;
        gazebo_msgs::ModelState modelstate;
        setmodelstate.request.model_state = modelstate;

        if (client.call(setmodelstate))
        {
            ROS_INFO("BRILLIANT!!!");
        }
        else
        {
            ROS_ERROR("Failed to call service ");
        }