对子类的未定义引用

我有一个子类：PointTwoD，它继承自BaseClass：locationdata。我收到此错误：在我的主函数中未定义对 PointTwoD 的引用，有人可以向我解释为什么吗？

基类位置数据.h

#include <string>
#include <iostream>
using namespace std;
class locationdata
{
  public:
  locationdata(); //default constructor
  locationdata(string,int,int,float,float); //constructor
 //setter
 void set_sunType(string);
 void set_noOfEarthLikePlanets(int);
 void set_noOfEarthLikeMoons(int);
 void set_aveParticulateDensity(float);
 void set_avePlasmaDensity(float);
 //getter 
 string get_sunType();
 int get_noOfEarthLikePlanets();
 int get_noOfEarthLikeMoons();
 float get_aveParticulateDensity();
 float get_avePlasmaDensity();

 float computeCivIndex();
 friend class PointTwoD;
      private:
  string sunType;
  int noOfEarthLikePlanets;
  int noOfEarthLikeMoons;
  float aveParticulateDensity;
  float avePlasmaDensity;
 };

基类位置数据.cpp

#include <iostream>
#include "locationdata.h"
using namespace std;
locationdata::locationdata()
{
  this->sunType = "";
  this->noOfEarthLikePlanets=0;
  this->noOfEarthLikeMoons=0;
  this->aveParticulateDensity=0;
  this->avePlasmaDensity=0;
}
locationdata::locationdata(string sunType , int noOfEarthLikePlanets , 
                       int noOfEarthLikeMoons , float aveParticulateDensity ,
                       float avePlasmaDensity)
{
    this->sunType = sunType;
this->noOfEarthLikePlanets = noOfEarthLikePlanets;
this->noOfEarthLikeMoons = noOfEarthLikeMoons;
this->aveParticulateDensity = aveParticulateDensity;
this->avePlasmaDensity = avePlasmaDensity;
}
void locationdata::set_sunType(string sunType)
{
  this->sunType = sunType;
 }
void locationdata::set_noOfEarthLikePlanets(int noOfEarthLikePlanets)
{ 
this->noOfEarthLikePlanets = noOfEarthLikePlanets;
}
void locationdata::set_noOfEarthLikeMoons(int noOfEarthLikeMoons)
{
this->noOfEarthLikeMoons = noOfEarthLikeMoons;
}
void locationdata:: set_aveParticulateDensity(float aveParticulateDensity)
{ 
this->aveParticulateDensity = aveParticulateDensity;
}
void locationdata::set_avePlasmaDensity(float avePlasmaDensity)
{
this->avePlasmaDensity = avePlasmaDensity;
}

string locationdata::get_sunType()
{ 
return this->sunType;
}
int locationdata::get_noOfEarthLikePlanets()
{
return this->noOfEarthLikePlanets;
}
int locationdata::get_noOfEarthLikeMoons()
{
return this->noOfEarthLikeMoons;
}
float locationdata::get_aveParticulateDensity()
{
return this->aveParticulateDensity;
}
float locationdata::get_avePlasmaDensity()
{
return this->avePlasmaDensity;
}
float locationdata::computeCivIndex()
{
string temp = this->get_sunType();
int sunTypePercent;
float CivIndex ;
if ( temp == "Type O")
{
sunTypePercent = 30;
}
else if ( temp == "Type B")
{
sunTypePercent = 45;
}
else if ( temp == "Type A")
{ 
sunTypePercent = 60; 
 }
else if ( temp == "Type F")
{ 
sunTypePercent = 75;
}
else if ( temp =="Type G")
{
 sunTypePercent = 90;
}
else if ( temp =="Type K")
{
 sunTypePercent = 80;
}
else if ( temp =="Type M")
{
 sunTypePercent = 70; 
}


           CivIndex=1.5;
          return CivIndex;
}

子类 PointTwoD.h

#include <iostream>
#include "locationdata.h"
using namespace std;
class PointTwoD:public locationdata
{
  public:
  PointTwoD();
  private:
  int x;
  int y;
  float civIndex;


};

子类点二D.cpp

   #include "PointTwoD.h"
 PointTwoD::PointTwoD()
{
  this ->x = 0;
  this->y = 0;
   this->set_sunType("");
   this->set_noOfEarthLikePlanets(0);
   this->set_noOfEarthLikeMoons(0);
   this->set_aveParticulateDensity(0);
   this->set_avePlasmaDensity(0);
}

主要功能

#include <iostream>
#include "PointTwoD.h"
using namespace std;
int main()
{
int choice;
PointTwoD test; //undefined reference
test.set_noOfEarthLikeMoons(10); // undefined reference
cout<<test.get_noOfEarthLikeMoons() //undefined reference
}