I'm currently learning inheritance and polymorphism in C++, and am coming across this issue when trying to create a child of a parent class that inherits and defines a virtual function.

The goal is for HumanPlayer to be a child of Player, and to create its own implementation of insertion() (a function that inserts an input into a tic-tac-toe board, once complete), however, I have run into a few errors that I can't seem to get by. I'm getting a dwarf error saying

There's an undefined reference to 'vtable for Player'. In function Player::Player() and Player::~Player().

As well as another dwarf error saying

Undefined reference to 'typeinfo for Player'.

Any help with this would be greatly appreciated.

Player.cpp:

#include <iostream>
  #include <string>
  #include "Player.h"
 
  Player::Player() {
      name = "Zoe";
      myState = 0;
      isWon = false;
 }

Player.h

#ifndef PLAYER_H
  #define PLAYER_H
 
  class Player {
      Player();
    protected:
      std::string name;
       int myState;
      bool isWon;
  public:
      virtual void insertion();
  };
 
 #endif

HumanPlayer.h :

 #ifndef HUMANPLAYER_H
  #define HUMANPLAYER_H
 
  #include "Player.h"
 
  class HumanPlayer : public Player {
  public:
      HumanPlayer();
      void insertion();
 protected:
      std::string Name1;
      std::string Name2;
       int humanCheck=0;
       std::string getName();
       int toInsert;
  };
 #endif

HumanPlayer.cpp

 #include <iostream>
  #include <string>
  #include "Player.h"
  #include "HumanPlayer.h"
 
  HumanPlayer::HumanPlayer() {
      if(humanCheck == 0) {
     std::cout<<"Player One type your name";
     scanf("%s", Name1);
     std::cout<<"Player Two type your name";
     scanf("%s", Name2);
     humanCheck++;
     }
 }
 
 
 void HumanPlayer::insertion() {
  if(humanCheck % 2 ==0) {
     std::cout<<Name2<<"'s turn, please enter an integer between 1 and 7";
         scanf("%i", &toInsert);
      } else {
     std::cout<<Name1<<"'s turn, please enter an integer between 1 and 7";
         scanf("%i", &toInsert);
      }
      humanCheck++;
 }