Undefined symbols for architecture x86_64 when Syntax is Correct

Question

I was working on some code for a class and checked everything, including a lot of similar errors, but nothing seem to be the same, could someone have a look?

I think it might have to do with c++ versions not being compatible with some code here but I'm not sure which.

I get the following error:

Undefined symbols for architecture x86_64:
  "__ZN15RobotController14initializeGameEi", referenced from:
      _main in ccZ9ege2.o
  "__ZN15RobotController8playGameEv", referenced from:
      _main in ccZ9ege2.o
  "__ZN15RobotControllerC1Ev", referenced from:
      _main in ccZ9ege2.o
ld: symbol(s) not found for architecture x86_64
collect2: error: ld returned 1 exit status

main.cpp

#include <iostream>
#include "RobotController.h"
#include "Robot.h"

using namespace std;

int main()
{
  string inputBuffer;
  int numberOfPlayers;
  RobotController gameManager;

  /// get the number of players
  do
    {
      cout << "How many players:";
      getline(cin, inputBuffer);
      numberOfPlayers = atoi( inputBuffer.c_str() );
    }
  while (numberOfPlayers < 1 || numberOfPlayers > 9);

  /// play the game over and over
  do
    {
      gameManager.initializeGame(numberOfPlayers);
      gameManager.playGame();
      cout << endl << "Play Again? [y/n]";
      getline(cin, inputBuffer);
    }
  while ( tolower(inputBuffer[0]) != 'n' );

  return 0;
}

Robot.h

#ifndef ROBOT_H
#define ROBOT_H

#include <sstream>
using namespace std;

class Robot {

public:
  Robot();
  void setName(string name);
  string getName();
  void print();
  bool addWheel();
  bool addAxle();
  bool addTorso();
  bool addPlunger();
  bool addHead();
  bool addAntenna();
  bool addCell();
  int countWheel();
  int countAxle();
  int countHead();
  int countTorso();
  int countPlunger();
  int countAntenna();
  int countCell();
  bool complete();
  void initialize();

private:
  string playerName_;
  int wheels_, axles_, torsos_, plungers_, heads_, antennae_, cells_;
};

#endif

Robot.cpp

#include "Robot.h"
#include <cstdlib>
#include <iomanip>
#include <iostream>

using namespace std;

void Robot::initialize(){
    wheels_=axles_=torsos_=plungers_=heads_=antennae_=cells_=0;
}

void Robot::print() {
  cout << endl;
  cout << playerName_ << "\'s Robot Parts: ";
  cout << "Wheels: " << wheels_ << "| Axles: " << axles_
       << "| Torso: " << torsos_ << "| Plungers: " << plungers_
       << "| Heads: " << heads_ << "| Antenna: " << antennae_
       << "| Power Cells: " << cells_ << endl;
  cout << endl;
}

void Robot::setName(string name) { playerName_ = name; }

string Robot::getName() { return playerName_; }

bool Robot::addWheel() {
  if (wheels_ < 3) {
    wheels_++;
    return true;
  }
  return false;
}

bool Robot::addAxle() {
  if ((axles_ < 3) && (wheels_ > axles_)) {
    axles_++;
    return true;
  }
  return false;
}

bool Robot::addTorso() {
  if ((torsos_ == 0) && (axles_ == 3)) {
    torsos_++;
    return true;
  }
  return false;
}

bool Robot::addPlunger() {
  if ((plungers_ == 0) && torsos_ == 1) {
    plungers_++;
    return true;
  }
  return false;
}

bool Robot::addHead() {
  if ((heads_ == 0) && (torsos_ == 1)) {
    heads_++;
    return true;
  }
  return false;
}

bool Robot::addAntenna() {
    if ((antennae_ < 2) && (heads_ == 1)){
    antennae_++;
    return true;
    }
    return false;
}

bool Robot::addCell() {
  if ((cells_ < 4) && (torsos_ == 1)) {
    cells_++;
    return true;
  }
  return false;
}

int Robot::countWheel() { return wheels_; }
int Robot::countAxle() { return axles_; }
int Robot::countHead() { return heads_; }
int Robot::countTorso() { return torsos_; }
int Robot::countPlunger() { return plungers_; }
int Robot::countAntenna() { return antennae_; }
int Robot::countCell() { return cells_; }

bool Robot::complete() {
  if (wheels_ == 3 && torsos_ == 1 && axles_ == 3 && plungers_ == 1 &&
      heads_ == 1 && cells_ == 4 && antennae_ == 2) {
    return true;
  }
  return false;
}

RobotController.h

#ifndef ROBOTCONTROLLER_H
#define ROBOTCONTROLLER_H

#include <vector>
#include "Robot.h"

class RobotController {
    public:
      RobotController();
      void initializeGame(int numPlayers);
      void playGame();
    private:
      vector<Robot> m_Robots_;
};

#endif

RobotController.cpp

#include <iostream>
#include <vector>
#include "RobotController.h"
#include "Robot.h"

void RobotController::initializeGame(int numPlayers)
{
    string name;
    m_Robots_.clear();
    m_Robots_.resize(numPlayers);

    for (int i = 0; i < numPlayers; i++){
        cout << "Player " << i+1 << " name: ";
        getline(cin, name);
        Robot robot;
        m_Robots_.push_back(robot);
        m_Robots_[i].setName(name);
        m_Robots_[i].initialize();
    }
}

void RobotController::playGame()
{
    int toss;
    srand(time(0));
    int k = 0;
    do{
        for (int i = 0; i < m_Robots_.size(); i++){
            cout << "Player " << i+1 << " starts" << endl;
            toss = rand() % 7 + 1;
            switch(toss){
                case 1:
                    m_Robots_[i].addWheel();
                    break;
                case 2:
                    m_Robots_[i].addAxle();
                    break;
                case 3:
                    m_Robots_[i].addTorso();
                    break;
                case 4:
                    m_Robots_[i].addPlunger();
                    break;
                case 5:
                    m_Robots_[i].addHead();
                    break;
                case 6:
                    m_Robots_[i].addAntenna();
                    break;
                case 7:
                    m_Robots_[i].addCell();
                    break;
            }
            m_Robots_[i].print();
        }
        k++;
    }while(!(m_Robots_[k].complete()));

    cout << "Winner is: " << m_Robots_[k].getName() << "!";

}