Joint controllers made using C++ and Python for RViZ (ROS)

JointController.cpp

#include "ros/ros.h"
#include "math.h"
#include "ros/time.h"
#include "sensor_msgs/JointState.h"

int main(int argv, char **argc) {
    // Initialize node
    ros::init(argv, argc, "CPP_Joint_State_Controller");
    // Node handler
    ros::NodeHandle nodeHandler;
    // Publisher
    ros::Publisher publisherObject = nodeHandler.advertise<sensor_msgs::JointState>("joint_states", 10);
    // Rate controller 5 Hz
    ros::Rate rateController = ros::Rate(20);
    // Variables
    float angle = 0.0;              // Angle
    bool increment = true;
    sensor_msgs::JointState msg;    // Message to be published
    msg.header.frame_id = "";           // Empty frame ID
    msg.name.resize(1);                 // A 1 unit size vector
    msg.position.resize(1);             // A 1 unit size vector
    msg.name[0] = "joint1";
    // Main iterative code
    while(ros::ok()) {
        // Update header
        msg.header.stamp = ros::Time::now();    // Assign time
        msg.position[0] = angle;
        publisherObject.publish(msg);
        msg.header.seq ++;                      // Next sequence
        if (increment) {
            angle += 90.0/20.0 * M_PI / 180.0;
        } else {
            angle -= 90.0/20.0 * M_PI / 180.0;
        }
        if (angle > M_PI || angle < -M_PI) {
            increment = !increment;
        }
        // Control rate
        rateController.sleep();
    }
    // End code
    return 0;
}

PyJointController.py

#!/usr/bin/env python
import rospy
from sensor_msgs.msg import JointState
import math

def main():
    # Initialize the node
    rospy.init_node("Py_JointStates")
    # Publisher object
    publisherObject = rospy.Publisher("joint_states", JointState, queue_size=10)
    # Rate controller
    rateController = rospy.Rate(20)
    # Variables
    msg = JointState()
    msg.header.frame_id = ""
    msg.name = ["joint1"]       # Joint name (array assignment)
    angle = 0
    increment = True
    # Main loop
    while(not rospy.is_shutdown()):
        # Initialize the time of publishing
        msg.header.stamp = rospy.Time.now()
        # Joint angle values
        msg.position = [angle]
        # Publish message
        publisherObject.publish(msg)
        # Increase sequence
        msg.header.seq += 1
        # Change angle value
        if increment:
            angle += 90.0/20.0 * math.pi / 180.0
        else:
            angle -= 90.0/20.0 * math.pi / 180.0
        if angle > math.pi or angle < - math.pi:
            increment = not increment
        # Delay execution to match rate
        rateController.sleep()

if __name__ == "__main__":
    try:
        main()
    except rospy.ROSInternalException:
        rospy.logfatal("Node crashed due to an internal exception")