Undefined reference to Car::Function

Question

I have been getting this error for my project and I can't figure out why I am getting it. While this is a common error, none of the other posts seem to have the correct solution.

Can't figure out this error:

Main function: (proj5.cpp)

#include <iostream>

#include "Vehicle.h"
#include "Car.h"

using namespace std;

int main(void){

  cout << "\n" <<
      "////////////////////////////\n" <<
      "/////    Base Tests    /////\n" <<
      "////////////////////////////" << endl;

  cout << endl << "Testing Base Default ctor" << endl;
  Vehicle v1;

  cout << endl << "Testing Base insertion operator" << endl;
  cout << v1 << endl;
  cout << "Base idgen: " << Vehicle::getIdgen() << endl;

  cout << endl << "Testing Base Parametrized ctor" << endl;
  float lla_rno[3] = {39.54, 119.82, 4500.0};
  Vehicle v99(99, lla_rno);

  cout << v99 << endl;
  cout << "Base idgen: " << Vehicle::getIdgen() << endl;

  cout << endl << "Testing Base Copy ctor" << endl;
  Vehicle v99_cpy( v99 );  

  cout << v99_cpy << endl;
  cout << "Base idgen: " << Vehicle::getIdgen() << endl;

  cout << endl << "Testing Base Assignment operator" << endl;
  v1 = v99_cpy;
  cout << v1 << endl;
  cout << "Base idgen: " << Vehicle::getIdgen() << endl;

  cout << endl << "Testing Base Move Function" << endl;
  float lla_new[3] = {37.77, 122.42, 52.0};
  v1.move( lla_new );  


  cout << "\n" <<
      "////////////////////////////\n" <<
      "/////   Derived Tests  /////\n" <<
      "////////////////////////////" << endl;

  cout << endl << "Testing Derived Default ctor" << endl;
  Car c1;

  cout << endl << "Testing Derived insertion operator" << endl;
  cout << c1 << endl;
  cout << "Derived idgen: " << Car::getIdgen() << endl;

  cout << endl << "Testing Derived Parametrized ctor" << endl;
  char plates_999[] = "Gandalf";
  Car c999(plates_999, 999, lla_rno);

  cout << c999 << endl;
  cout << "Derived idgen: " << Car::getIdgen() << endl;

  cout << endl << "Testing Derived Copy ctor" << endl;
  Car c999_cpy( c999 );  

  cout << c999_cpy << endl;
  cout << "Derived idgen: " << Car::getIdgen() << endl;

  cout << endl << "Testing Derived Assignment operator" << endl;
  c1 = c999_cpy;
  cout << c1 << endl;
  cout << "Derived idgen: " << Car::getIdgen() << endl;

  cout << endl << "Testing Derived Move Function" << endl;
  c1.move( lla_new );  

  cout << "\n" <<
      "////////////////////////////\n" <<
      "/////    Tests Done    /////\n" <<
      "////////////////////////////" << endl;

  return 0;

}

Car.cpp:

    #include <iostream>
    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
    #include "Car.h"
    #include "Vehicle.h"
    using namespace std;
    Car::Car()
    {
    m_throttle = 0;
    const int m_vin = getIdgen();
    m_lla = (float*)malloc(sizeof(float) * 3);
    cout << "Car #" << m_vin << ": Default-ctor" << endl;
}
Car::Car(char * plates, int vin, float * lla)
{
    strcpy(m_plates, plates);
    const int m_vin = *vin;
    for(int i = 0; i < 3; i++)
    {
        m_lla[i] = lla[i];
    }
    cout << "Car # " << m_vin <<": Parametrized-ctor" << endl;
}
Car::Car(Car & old)
{
    const int m_vin = old.getVin();
    strcpy(m_plates, old.getPlates());
    setLLA(*(old.getLLA()));
    cout << "Car #" << m_vin << ": Copy-ctor" << endl;
}
Car::~Car()
{
    cout << "Car #" << m_vin << ": Dtor" << endl;
}
char * Car::getPlates()
{
    return m_plates;
}
void Car::operator=(Car & car)
{
    this->m_throttle = getThrottle();
    strcpy(this->m_plates, car.getPlates());
    const int m_vin = car.getVin();
    this->m_lla = car.getLLA();
    cout << "Car #" << m_vin << ": Assignment" << endl;
}
int Car::getThrottle()
{
    return m_throttle;
}
void Car::setThrottle(int num)
{
    m_throttle = num;
}
void Car::setPlates(char * plates)
{
    strcpy(m_plates, plates);
}
void Car::drive(int * num)
{
    m_throttle = *num;
}
void Car::move(float * lla)
{
    this->setLLA(*lla);
    cout << "Car #" << m_vin << ": DRIVE to destination, with throttle @ 75" << endl; 
}

Car.h: #

ifndef CAR_H_
    #define CAR_H_
    #include "Vehicle.h"
    class Car: public Vehicle
    {
        public:
            Car();
            Car(char * plates, int vin, float * lla);
            Car(Car & old);
            ~Car();
            void operator=(Car & car);
            char * getPlates();
            int getThrottle();
            void setPlates(char * plates);
            void setThrottle(int throttle);
            void drive(int * throttle);
            void move(float * lla);

        private:
            char * m_plates;
            int m_throttle;
    };
    #endif

Here is the error:

/tmp/cczSuMnH.o: In function main': proj5.cpp:(.text+0x3bd): undefined reference toCar::Car()' proj5.cpp:(.text+0x487): undefined reference to Car::Car(char*, int, float*)' proj5.cpp:(.text+0x50e): undefined reference toCar::Car(Car&)' proj5.cpp:(.text+0x595): undefined reference to Car::operator=(Car&)' proj5.cpp:(.text+0x61f): undefined reference toCar::move(float*)' proj5.cpp:(.text+0x673): undefined reference to Car::~Car()' proj5.cpp:(.text+0x67f): undefined reference toCar::~Car()' proj5.cpp:(.text+0x68b): undefined reference to Car::~Car()' proj5.cpp:(.text+0x6da): undefined reference toCar::~Car()' proj5.cpp:(.text+0x6eb): undefined reference to Car::~Car()' /tmp/cczSuMnH.o:proj5.cpp:(.text+0x6fc): more undefined references toCar::~Car()' follow collect2: error: ld returned 1 exit status