同一项目中两个类之间的 c++ LNK2019 错误

Question

所以我正在尝试创建一个模仿扫雷游戏的程序。我仔细检查了头文件、class 名称，并确保头文件#included 在其他 cpp 文件中，但是当我尝试构建程序时，我在 "Main" class 我有。

完整错误：

Error 1 error LNK2019: unresolved external symbol "public: __thiscall Board::Board(int,int,int)" (??0Board@@QAE@HHH@Z) referenced in function _main \fpsb\g\gathmr26\visual studio 2013\Projects\Minesweeper\Minesweeper\Main.obj Minesweeper

我大概花了大约 2 个小时在 Whosebug 和其他地方查看答案，但一无所获。我已经运行仔细阅读了 this MSDN page, and every "common cause" in this popular answer 中的每个要点，其中 none 似乎适用于我的情况。我还尝试了 MSDN 页面上的所有 "Diagnosis tools" 选项，他们所做的只是让我更加困惑。

最接近我的情况（据我所知）是 this question 除了我的所有代码都在一个项目中，而不是多个项目中。回答该问题的人之一说 "I typed this code into my Visual Studio and it worked fine"，假设这些文件在一个项目中。我不明白为什么当我在这里遇到几乎相同的情况时，为什么那个答案在那里起作用。

所以，无论如何，这是代码：

Main.cpp

#include <iostream>
#include <string>
#include "Cell.h"
#include "Board.h"

int main() {
    Board *bee;
    bee = new Board(50, 50, 50);

    std::cout << "board created";

    return 0;
}

Board.cpp

#include <iostream>
#include <string>
#include <ctime>
#include <cstdlib> 
using namespace std;
#include "Cell.h"
#include "Board.h"
#ifndef BOARD_H
#define BOARD_H

// Board class. Used to create an array of cell objects to function as data model for Minsweeper game.
class Board
{
private:
int width; // number of columns in board
int height; // number of rows in board
int mines; // number of mines stored in board
Cell*** cells; // array storing cell objects

public:

// Constructor for board. Takes number of columns, rows, and mines as parameters
Board::Board(int cols, int rows, int numMines) {
    width = cols;
    height = rows;
    mines = numMines;
    cells = new Cell**[height];
    for (int i = 0; i < height; i++) {
        cells[i] = new Cell*[width];
    }
    int c = 0;
    int r = 0;
    while (r < height)
    {
        while (c < width)
        {
            setCell(c, r, CellValue::COVERED_CELL);
            c++;
        }
        c = 0;
        r++;
    }
    int m = 0;
    while (m < numMines)
    {
        std::srand(std::time(nullptr));
        int x = generateRandomNumberInRange(0, width - 1);
        int y = generateRandomNumberInRange(0, height - 1);
        if (!(getCellVal(x, y) == MINE))
        {
            setCell(x, y, CellValue::MINE);
            m++;
        }
    }
}

    // Accessor for width field
int Board::getWidth()
{
    return width;
}

// Accessor for height field
int Board::getHeight()
{
    return height;
}

// Accessor for mines field
int Board::getMines()
{
    return mines;
}

// Function to access value of cell located in array where x is column parameter and y is row parameter
CellValue Board::getCellVal(int x, int y)
{
    CellValue value = CellValue::INVALID_CELL;

    if (!(x < 0 || x >(width - 1) || y < 0 || y >(height - 1)))
    {
        Cell temp = *cells[x][y];
        value = temp.getValue();
    }

    return value;
}

// Function to set value of cell located in array where x is column parameter and y is row parameter
void Board::setCell(int x, int y, CellValue value)
{
    if (!(x < 0 || x >(width - 1) || y < 0 || y >(height - 1)))
    {
        Cell temp = *cells[x][y];
        temp.setValue(value);
    }
}

// Function to determine if game is lost
// Loops through array to see if there are any UNCOVERED_MINES
// If so, returns true, game ends, as you've lost :(
// If not, returns false and game can continue
// Should run after every click action in game
bool Board::isGameLost()
{
    bool isLost = false;
    int c = 0;
    int r = 0;
    while (r < height)
    {
        while (c < width)
        {
            if (getCellVal(c, r) == UNCOVERED_MINE)
            {
                isLost = true;
            }
            c++;
        }
        c = 0;
        r++;
    }
    return isLost;
}

// Function to determine if game is won
// Loops through array to determine if there are any falsely flagged mines, unflagged mines, covered cells, or uncovered mines
// If there are, returns false and game continues
// If not, returns true, games ends, you've won :)
bool Board::isGameWon()
{
    bool isWon = true;
    int c = 0;
    int r = 0;
    while (r < height)
    {
        while (c < width)
        {
            CellValue value = getCellVal(c, r);
            if ((value == FLAG) ||
                (value == MINE) ||
                (value == COVERED_CELL) ||
                (value == UNCOVERED_MINE))
            {
                isWon = false;
            }
            c++;
        }
        c = 0;
        r++;
    }
    return isWon;
}

};


#endif

Board.h

#include <iostream>
#include <string>
#include "Cell.h"
#ifndef BOARD_H
#define BOARD_H

class Cell;
enum CellValue;

class Board 
{
private: 
    int width;
    int height;
    int mines;
    Cell*** cells;

public:
    Board(int cols, int rows, int numMines);
    int getWidth();
    int getHeight();
    int getMines();
    CellValue* getCellVal(int x, int y);
    void setCell(int x, int y, CellValue value);
    void uncoverCell(int x, int y);
    void flagCell(int x, int y);
    bool isGameLost();
    bool isGameWon();
};

#endif

我知道这是人们常犯的一个错误，在 Whosebug 上有很多关于此的问题，但目前，我还没有发现任何与我在这里找到的问题相符的问题。这里有什么问题？

Answer 1

您似乎在混合使用头文件和源文件。您的 cpp 文件包含一个 class 声明，其中定义了所有函数。这不是 cpp 文件的样子。它应该只包含函数声明：

Board::Board(...)
{
    ...
}

bool Board::IsGameWon...

等...

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