subscriber callback not running (c++)

edit

so I've been stuck on this for a while now and have come to realize that the issue with my code is that for some reason the callback function for my subscriber never seems to run and I can't understand why for the life of me.

I'm using 3 files to run my code in order to make sure that in the future everything will be as modular as possible and I can simply swap 1 or 2 lines in my main function file to make my turtlebot do different things based on the functions in the function file.

To make sure the callback was running I added a cout << "test" << endl; to the function just to see if anything prints, and it doesn't. So I assume that's where my major problem lies.

Any help would be greatly appreciated.

The files are:

mainfunction.cpp
#include <iostream>
#include <ros/ros.h>
#include <geometry_msgs/Twist.h>
#include <nav_msgs/Odometry.h>
#include <std_msgs/Empty.h>
#include "TurtleFunction.cpp"
#include "TurtleFunction.h"

#include <sstream>
#include <string>
#include <cmath>
#include <math.h>

using namespace std;


int main(int argc, char** argv){

    // Initialize ROS
    ros::init(argc, argv, "test3");
    ros::NodeHandle nh;

    // Define Global Variables for use
    cmd_pub = nh.advertise<geometry_msgs::Twist>("/cmd_vel_mux/input/teleop", 50);
    reset_pub = nh.advertise<std_msgs::Empty>("/mobile_base/commands/reset_odometry", 1);
    OdomSub = nh.subscribe<nav_msgs::Odometry>("/odom",50,processodom);
    resetOdom(); // Reset the Odometry of the Turtlebot
    ros::Rate r(50);
    ros::spinOnce();

    // Define Initial Velocity Variables for TurtleBot
    double v = 0.1;
    double theta = 0.01;

    int i = 0;

    /*
     * Begin Infinite Loop.
     * First Function is our method of identifying other TurtleBots (if applicable)
     * Second Function is our chosen Control Law (if applicable)
     * Third Function is how we drive the TurtleBot
     */
    while(ros::ok()){
        UnicycleModel();
        cout << "this is working" << i << endl;
        i++;
        ros::spinOnce();
    }

    return 0;
}

The function file:

TurtleFunction.cpp

#include <iostream>
#include <ros/ros.h>
#include <geometry_msgs/Twist.h>
#include <nav_msgs/Odometry.h>
#include <std_msgs/Empty.h>
#include "TurtleFunction.h"


#include <sstream>
#include <string>
#include <cmath>
#include <math.h>

using namespace std;

/*
 * The Movement Function allows us to test that our Turtlebot can be controlled usings a
 * separate function file. It's also the "block" we use to make the movement modules for the
 * Turtlebot (i.e.- Unicycle Model or Feedback Linearization) work.
 * It takes three (3) inputs;
 * 1) the ros::Publisher that we will use to publish to the Turtlebot
 * 2) the desired linear velocity
 * 3) the desired rotational velocity
 * Using these three (3) inputs, it publishes a command to the Turtlebot telling it how to move
 */
void Movement(double v,double theta){

    // geometry_msgs::Twist cmd_msg;

    cmd_msg.linear.x  = v;
    cout << "v = " << cmd_msg.linear.x << endl;
    cmd_msg.angular.z  = theta;
    cout << "theta = " << cmd_msg.angular.z << endl;
    cmd_pub.publish(cmd_msg); //send

    ros::spinOnce();
}

/*
 * The Unicycle Model is the classic model used for describing the dynamics
 * of the Turtlebot. The Unicycle Model Function allows us to find the desired linear velocity
 * and rotational velocity which we can ...