我目前正在尝试创建一个井字游戏，由玩家共享的棋盘对象上的玩家类创建的两个玩家对象交替玩游戏。据我所知，我已经完成了程序，但是当我尝试构建时，我得到了这些错误，似乎无法找到原因。我对面向对象编程比较陌生。以下是我得到的错误：
1>Player.obj : error LNK2005: "public: __thiscall Player::Player(class Board *,char)" (??0Player@@QAE@PAVBoard@@D@Z) already defined in Connect_Four_Game.obj
1>fatal error LNK1169: one or more multiply defined symbols found
以下是代码：
#ifndef ___PLAYER_H___
#define ___PLAYER_H___
#include <iostream>
#include "Board.h"
using namespace std;
class Player {
private:
Board * sharedboard;
char player_char;
public:
Player(Board *shared_board, const char player_char);
bool play(int &choice);
bool wins();
bool columnFull(int&choice);
};
Player:: Player(Board *shared_board,const char player_char)
: player_char(player_char), sharedboard(shared_board)
{}
#endif
Board header file：
#ifndef ___BOARD_H___
#define ___BOARD_H___
#include <iostream>
#include <vector>
using namespace std;
class Board {
public:
vector<vector<char>> holder;
void displayBoard();
bool isBoardFull();
Board()
{
vector<vector<char>>holder(7, vector<char>(7, 'A'));
}
};
#endif
播放器cpp文件：
#include <iostream>
#include "Player.h"
using namespace std;
bool Player::columnFull(int &choice)//DONE
{
for (int i = 6; i >= 0; i--)
{
if(sharedboard->holder[i][choice]=='A')//if the choice is not full
{
sharedboard->holder[i][choice] = player_char;//put the players character(X or O here)
return false;
}
else//if the choive is full
{
return true;
}
}
}
bool Player::play(int &choice)//DONE
{
if(choice < 0 )
{
cout << "Choice is not valid." << endl;
return false;
}
else if(choice > 6)
{
cout << "Choice is not valid." << endl;
return false;
}
else if(columnFull( choice))//if its true then its full
{
cout << "Choice is not valid." << endl;
return false;
}
else
{
sharedboard->displayBoard();//if previous ones were false, then the place was empty, and filled, therefore the board will be displayed
}
}
bool Player::wins()//if the player wins
{
int o = 0;
int x = 0;
for (int i = 0; i < 7; i++)//HORIZONTAL
{
for (int j = 0; j < 7; j++)
{
if (sharedboard->holder[i][j] == 'O')
{
o++;
}
else if (sharedboard->holder[i][j] == 'X')
{
x++;
}
if (o == 4)//if O is four horizantily
{
cout << "Player2 wins!" << endl;
sharedboard->displayBoard();
return true;
}
else if (x == 4)//if X is four horizantily
{
cout << "Player1 wins!" << endl;
sharedboard->displayBoard();
return true;
}
}
}//HORIZONTAL
o = 0;
x = 0;
for (int i = 0; i < 7; i++)//VERTICALLY
{
for (int j = 0; j < 7; j++)
{
if (sharedboard->holder[j][i] == 'O')
{
o++;
}
else if (sharedboard->holder[j][i] == 'X')
{
x++;
}
if (o == 4)//if O is four vertically
{
cout << "Player2 wins!" << endl;
sharedboard->displayBoard();
return true;
}
else if (x == 4)//if X is four vertically
{
cout << "Player1 wins!" << endl;
sharedboard->displayBoard();
return true;
}
}
}//VERTICALLY
}
Board cpp文件：
#include "Board.h"
#include<iostream>
using namespace std;
void Board::displayBoard()//DONE
{
for (int i = 0; i < 7; i++)
{
for (int j = 0; j < 7; j++)
{
cout << holder[i][j] << " ";
}
cout << endl;
}
}
bool Board::isBoardFull()//DONE-CORRECTED
{
for (int i = 0; i < 7; i++)
{
for (int j = 0; j < 7; j++)
{
if (holder[i][j] == 'A')
{
return false;//game continues
}
else if(((i==6)&&(j==6)))
{
return true;//ends in tie
}
}
cout << endl;
}
}
主要源文件：
#include<iostream>
#include<string>
#include "Board.h"
#include "Player.h"
using namespace std;
int main()
{
Board myBoard = Board();
/*
//Create your player objects based on your choice of approach to share an object.
//The parameters "..." are left for you to set.
Player player1 = Player(...);
Player player2 = Player(...);
*/
Player player1(&myBoard, 'X');
Player player2(&myBoard, 'O');
int col, turn = 0;
bool continueGame = true;
bool validMove = false;
while(continueGame)
{
myBoard.displayBoard();
if(turn == 0)
{
cout << "Player 1 turn: " << endl;
cin >> col;
validMove = player1.play(col);
if(player1.wins())
{
continueGame = false;
cout << "Player1 won the game!" << endl;
}
}
else if(turn == 1)
{
cout << "Player 2 turn: " << endl;
cin >> col;
validMove = player2.play(col);
if(player2.wins())
{
continueGame = false;
cout << "Player2 won the game!" << endl;
}
}
if(continueGame) {
//If a valid move has been done, change the turn
if(validMove) {
turn = (turn + 1) % 2;
}
if(myBoard.isBoardFull())
{
continueGame = false;
cout << "Noone won the game!" << endl;
}
}
}
cout << "Game is over!" << endl;
cout << "Final state of the board: " << endl;
myBoard.displayBoard();
return 0;
}
我没有发布整个播放器cpp文件，因为它大约有600行，并且只有重复进行对角线搜索而没有别的。谢谢你。
答案 0 :(得分：1)
错误表示您定义了多个符号。最有可能的是，您在其他一些文件中多次（直接或间接）包含了Player.cpp文件（而不是Player.h）（您没有共享Connect_Four_Game文件）。
我建议你做一些研究：如果你包含.cpp文件怎么办？阅读有关声明，定义，多重内容，....这也很有用： Already defined in .obj - no double inclusions
我开始就像你一样，提出不好的问题（我想每个人都这样做）。下次，您应该尝试检测链接器错误发生的位置，并知道链接器错误是什么。
我很清楚C ++的开始日子。正如您在此代码中明显付出的努力，请允许我给您一些与您发布的代码相关的建议。
<强>设计
在编码之前，请正确进行设计。在玩家之间建立共享董事会是可以的。你也可以有一个玩家订阅的棋盘。无论哪种方式：
Board 应该了解自己的一切。那就是：玩家不应该访问属性＆＃34; holder＆＃34;董事会，看看是否正在占用一个正方形。玩家应该向董事会询问：该广场是免费的吗？
同样，columnFull不应该是 Player 的方法。
<强>代码
您应该尝试使用现代C ++。我重写了一些你的代码。
播放器构造函数：使用智能指针
Player(const std::shared_ptr<Board>& board, std::string&& name) :
m_name(std::move(name)), m_board(board)
{}
您的主文件现在将如下所示：
std::shared_ptr<Board> myBoard = std::make_shared<Board>();
Player me(myBoard,"Me");
Player you(myBoard,"You");
参考内置类型：
bool play(const int choice) // no reference to built-in types unless needed
尽可能使用const：
bool wins() const // should be const, you don't want to modify "this"
使用私有成员，字符串而不是char和智能指针
private:
std::shared_ptr<Board> m_board; // use smart pointers
std::string m_name; // not playerChar -> it's obvious its about the player
看看现代C ++有多好：
void display() const // use const if you don't modify this
{
// you had hardcoded numbers here (7)... try to avoid that, keep the code generic
for (const auto& v : m_holder) // you do have access to C++11 I hope?
{
for (const auto& h : v)
std::cout << h << std::endl;
}
}
使用标准库：
bool isFull() const // try to use the wonderful standard library, your code will be much more readable
{
for (const auto& v : m_holder)
{
auto it = std::find_if(v.begin(),v.end(),[](const std::string& h){ return h.empty(); });
if (it==v.end())
return false;
}
return true;
// cout << endl shouldn't be in this function which checks if the board is full...
}
也许有些typedef可以保持代码清洁？另外，使用_或m_作为属性。尽可能保持属性的私密性。
private: // try to keep members in private so you control who changes them
// maybe use typedef? you use that type multiple times
typedef std::vector<std::vector<std::string>> HolderType;
HolderType m_holder; // for members, use _ or m_
<强>总体
这当然是一份非常不完整的建议清单。但这些是你代码的主要缺陷。
我希望这很有帮助。