ROS Serial Arduino "Hello World" Error

edit

Just getting rosserial setup after a few days of issues. When trying to run the Hello World example (code below) I error out (also below). Any help would be great!

*
 * rosserial Publisher Example
 * Prints "hello world!"
 */

// Use the following line if you have a Leonardo or MKR1000
//#define USE_USBCON

#include <ros.h>
#include <std_msgs/String.h>

ros::NodeHandle nh;

std_msgs::String str_msg;
ros::Publisher chatter("chatter", &str_msg);

char hello[13] = "hello world!";

void setup()
{
  nh.initNode();
  nh.advertise(chatter);
}

void loop()
{
  str_msg.data = hello;
  chatter.publish( &str_msg );
  nh.spinOnce();
  delay(1000);
}

Error code

Arduino: 1.8.15 (Linux), Board: "Arduino Uno"

Hello_world:2:14: error: expected constructor, destructor, or type conversion before 'Publisher'
  * rosserial Publisher Example
              ^~~~~~~~~
exit status 1
expected constructor, destructor, or type conversion before 'Publisher'


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