Array data from arduino

edit

Hi i trying to send array data from arduino to my node but i have problems with it. I'm reading data from accelerometer and want to send xyz values in array message. Code compile properly but when i tryng to start serial connection with arduino it stucks even if i trying to send only one value. What is wrong here?

/*
 * rosserial Publisher Example
 * Prints "hello world!"
 */
#include "I2Cdev.h"
#include "MPU6050.h"
#include <Wire.h>
#include <ros.h>
//#include <std_msgs/Int16.h>
#include <std_msgs/Int16MultiArray.h>

MPU6050 accelgyro;
int16_t ax, ay, az;
int16_t gx, gy, gz;

ros::NodeHandle  nh;

//std_msgs::Int16 x;
std_msgs::Int16MultiArray xar;


//ros::Publisher inty("inty", &x);
ros::Publisher intyarr("intyarr", &xar);

void setup()
{
  nh.initNode();
  nh.advertise(intyarr);
  Wire.begin();
  accelgyro.initialize();
}

void loop()
{
  accelgyro.getMotion6(&ax, &ay, &az, &gx, &gy, &gz);
  //x.data = ay;
  //inty.publish(&x);
  xar.data[1]=ax;
  intyarr.publish(&xar);
  nh.spinOnce();
  delay(1000);
}

Also i want to resend data from my node to arduino to send it into robot but i dont know how to do it.

void messageCb( const std_msgs::Int16& msg){
  //digitalWrite(13, HIGH-digitalRead(13));   // blink the led
  msg->data;
}

Code like this doesn't work in Arduino IDE.