Visual Studio 2010 - 致命错误 LNK1120: 1 unresolved externals； C++

Question

我收到了错误：

asteroid.obj：错误 LNK2001：无法解析的外部符号“私有： 静态字符 (* Asteroid::Image)[4]" (?Image@Asteroid@@0PAY03DA) 1>C:\用户\约翰\文档\Visual Studio 2010\Projects\assignment3.1\Debug\assignment3.1.exe：致命错误 LNK1120: 1 个未解决的外部问题

而且我没有看到代码中的问题。我的程序中唯一改变的是我的“Image”和“LoadImage”成员函数。

这就是我在头文件中的代码现在的样子（跳过一些公共函数）

class Asteroid
{
private:
static const int ROWS = 3;
static const int COLUMNS = 4;
int row;
int column;
int row_size;
int column_size;
unsigned int ore_value;
static char Image[ROWS][COLUMNS];

public: static void LoadImage();
};

这就是 .cpp 文件中 LoadImage() 函数的样子

void Asteroid::LoadImage()
{
string myline;
ifstream asteroid_image_data("asteroid.txt");
if (asteroid_image_data.fail())
{
    cerr << "Asteroid image file is not available" << endl;
    return;
}

for (unsigned int i = 0; i < ROWS; i++)
{
    getline(asteroid_image_data, myline, '\n');
    if (!asteroid_image_data)
    {
        cerr << "Asteroid image file is missing some data" << endl;
        return;
    }

    for (unsigned int j = 0; j < COLUMNS; j++)
    {
        Image[i][j] = myline[j];
    }
}
asteroid_image_data.close();
}

来自main.cpp的调用只是

Asteroid::LoadImage();

Answer 1

你必须为静态字符数组添加一个定义

下面是头cpp文件中的操作方法：

   char Asteroid::Image[3][4] = { {'0','0','0','0'},
                                  { '0','0','0','0'},
                                  { '0','0','0','0'}
                                };

或者

   char Asteroid::Image[3][4];

这样没问题，行得通

Your header file (Header.h):

        #pragma once

        #include <string>

        using namespace std;

        class Asteroid
        {
        private:
            static const int ROWS = 3;
            static const int COLUMNS = 4;
            int row;
            int column;
            int row_size;
            int column_size;
            unsigned int ore_value;
            static char Image[ROWS][COLUMNS];

            public: static void LoadImage();
        };

Header.cpp：

#include "Header.h"
#include <fstream>
#include <iostream>

using namespace std;

void Asteroid::LoadImage()
{
    string myline;
    ifstream asteroid_image_data("asteroid.txt");

    if (asteroid_image_data.fail())
    {
        cerr << "Asteroid image file is not available" << endl;
        return;
    }

    for (unsigned int i = 0; i < ROWS; i++)
    {
        getline(asteroid_image_data, myline, '\n');

        if (!asteroid_image_data)
        {
            cerr << "Asteroid image file is missing some data" << endl;
            return;
        }

        for (unsigned int j = 0; j < COLUMNS; j++)
        {
            Image[i][j] = myline[j];
        }
    }
    asteroid_image_data.close();
}

char Asteroid::Image[3][4];

主文件（Source.cpp）：

    #include <iostream>
    #include "Header.h""

    int main() {

        Asteroid::LoadImage();
    }