链接器错误与C ++

Question

我在C ++中遇到链接器错误。我一直试图弄清楚并试图使用gcc，clang ++和g ++（我正在使用它），但错误仍然没有消失。

这是我收到的错误消息：

Undefined symbols for architecture x86_64:
  "Game::play()", referenced from:
   _main in main-537fd9.o
  "Game::Game(int, int, int)", referenced from:
  _main in main-537fd9.o
  "Game::~Game()", referenced from:
  _main in main-537fd9.o
  ld: symbol(s) not found for architecture x86_64
  clang: error: linker command failed with exit code 1 (use -v to see invocation)

有人可以帮帮我吗？谢谢！

main.cpp中：

#include "Game.h"
int main()
{    
srand(static_cast<unsigned int>(time(0)));
  // Create a game
  // Use this instead to create a mini-game:   
Game g(3, 3, 2);
Game g(9, 10, 40);
  // Play the game
g.play();
}

Game.cpp：

#include "Game.h"
#include "globals.h"
#include "Pit.h"
#include "Player.h"
#include "Snake.h"
Game::Game(int rows, int cols, int nSnakes)
{
    if (nSnakes < 0)
{
cout << "***** Cannot create Game with negative number of snakes!" << endl;
exit(1);
}
if (nSnakes > MAXSNAKES)
{
    cout << "***** Cannot create Game with " << nSnakes
         << " snakes; only " << MAXSNAKES << " are allowed!" << endl;
    exit(1);
}
if (rows == 1  &&  cols == 1  &&  nSnakes > 0)
{
    cout << "***** Cannot create Game with nowhere to place the snakes!" << endl;
    exit(1);
}

    // Create pit
m_pit = new Pit(rows, cols);

    // Add player
int rPlayer = 1 + rand() % rows;
int cPlayer = 1 + rand() % cols;
m_pit->addPlayer(rPlayer, cPlayer);

  // Populate with snakes
while (nSnakes > 0)
{
    int r = 1 + rand() % rows;
    int c = 1 + rand() % cols;
      // Don't put a snake where the player is
    if (r == rPlayer  &&  c == cPlayer)
        continue;
    m_pit->addSnake(r, c);
    nSnakes--;
}
}

Game::~Game()
{
    delete m_pit;
}

void Game::play()
{
    Player* p = m_pit->player();
    if (p == nullptr)
{
    m_pit->display("");
    return;
}
string msg = "";
while ( ! m_pit->player()->isDead()  &&  m_pit->snakeCount() > 0)
{
    m_pit->display(msg);
    msg = "";
    cout << endl;
    cout << "Move (u/d/l/r//q): ";
    string action;
    getline(cin,action);
    if (action.size() == 0)
        p->stand();
    else
    {
        switch (action[0])
        {
          default:   // if bad move, nobody moves
            cout << '\a' << endl;  // beep
            continue;
          case 'q':
            return;
          case 'u':
          case 'd':
          case 'l':
          case 'r':
            p->move(decodeDirection(action[0]));
            break;
        }
    }
    m_pit->moveSnakes();
}
m_pit->display(msg); }