c++ - LNK2019 : Unresolved External Symbol . ..函数_main中引用

Question

我正在上编程入门课，所以我希望这个问题不会太糟糕。到目前为止，我已经修复了 Main 函数中的所有问题，但是后来我取消了对 Blob 函数调用的注释，出现了一个我显然无法弄清楚的错误。我已经对其进行了研究，但还没有找到任何适合我的问题的东西。

我相信它与我添加的 ** 有关，以解决我的 2D 数组的先前问题(这是分配所必需的)。我在代码顶部包含了注释，以阐明程序的目标。

错误是:

error LNK2019: unresolved external symbol "void __cdecl Blob(char * *,int,int)" (?Blob@@YAXPAPADHH@Z) referenced in function _main c:\Users\Laura\documents\visual studio 2010\Projects\pr9_lt12e\pr9_lt12e\p9_lt12e.obj

此外，输出数组的第一行向左偏移 10 个空格。第 13 列应该有一个 'X'，但它显示在 3。我手动更改了数组的值，以便 arr[0][12] = 'X'(在打印出数组之前)但位置确实不变。我仍然可以在不修复此程序的情况下使用该程序，因为它只会减少几个点数。

我的整个代码是:

/*
         SUMMARY 
           This program will read in data from a file and store it in a two-dimensional array. 
           From there it will detect all of the groupings of characters, or "blobs", in the file and count them.

         INPUT 
           The program will read in information from a file called "blob.txt".

           BAD DATA CHECKING: 
                N/A

         OUTPUT 
            The program will output the amount of blobs in the file.

         DATA STRUCTURES
            N/A

         ASSUMPTIONS  
          -The file will have 20 records. Each record will be 70 characters long and the character 
            will be either an X or a blank space/whitespace.

*/

#include <iostream>
#include <iomanip>
#include <cmath>    
#include <fstream>
#include <string>
using namespace std;

//GLOBAL CONSTANTS
const int   ONE_D = 22,
            TWO_D = 72,
            SEVEN = 7;

const char  X = 'X',
            B = ' ';

//FUNCTION PROTOTYPES
void Blob(char**, int, int);    //Retrieves data from the file and places it into the array


//MAIN FUNCTION
int main()
{
    //Declare variables
    ifstream file;

    string line;

//  char character;

    int index1 = 0,
        index2 = 0,
        col1 = 0,
        col2 = 0,
        blobCount = 0;

    //Declare the 2D array. From course website.
    char ** arr;
    arr = new char * [ONE_D];
    for (index1 = 0; index1 < ONE_D; index1++)
        arr[index1] = new char [TWO_D];

    //Welcome message
    cout << "Welcome to the Recursive Blob Finder program!\n\n";

    //Open the file
    file.open("blob.txt");

    //Check to see if file has been opened
    if (file.is_open())
        cout << "The file has been opened!\n\n";
    else
        cout << "The file has not been opened!\n\n";

    //Read in data from the file and write to the array
    for (index1 = 0; index1 < 20; index1++) {
        getline(file, line);
        strcpy_s(arr[index1], 72, line.c_str()); 
    }

    ////Row 1 is offset by -10. Adjust first row.
    //arr[0][2] = B;
    //arr[0][12] = X;

    //Clear non-'X' cells
        for (index1 = 0; index1 < 22; index1++) {
            for (index2 = 0; index2 < 72; index2++) {
                if (arr[index1][index2] != X)
                    arr[index1][index2] = B;
            }
        }

    //Print numbered lines
    for (col1 = 1; col1 < 8; col1++)    
        cout << "         " << col1;

    cout << endl;

    for (col2 = 1; col2 < 8; col2++)    
        cout << "1234567890";

    cout << endl;    //EDIT IS HERE

    //Print array
    for (index2 = 0; index2 < 20; index2++) {

        for (index1 = 0; index1< 70; index1++)
            cout << arr[index2][index1];

        cout << endl;
    }

    //Search array for 'X' characters
    for (index1 = 0; index1 < 20; index1++)     {

        for (index2 = 0; index2 < 70; index2++) {

            //When X is found, add 1 to blob count. Blob function will clear out the remaining blob characters
            if (arr[index1][index2] == X)   {
                blobCount++;
                Blob(arr, index1, index2);
            }
        }
    }

    //Close the file
    file.close();

    return 0;

}


//OTHER FUNCTIONS   

//Name: Blob
//Description:  Recursive function to find and clear each blob.
void Blob(char **c[ONE_D][TWO_D], int row, int col)  
{
        //Eliminate one blob at a time

    //Potential positions for 'X' after clearing the last X:         Ox
    //                                                              xxx


    if (**c[row][col]==X)   {
        **c[row][col] = B;

        //Test for X's connected to current blob
        if (**c[row][col+1]==X)
            Blob (c, row, col);

        if (**c[row+1][col-1]==X)
            Blob (c, row, col);

        if (**c[row+1][col] == X)
            Blob (c, row, col);

        if (**c[row+1][col+1]==X)
            Blob (c, row, col);
    }   
}

我尝试过的一些事情包括更改原型(prototype):

void Blob(char** c[ONE_D][TWO_D], int, int);

函数调用:

Blob(arr[][], index1, index2);
Blob(arr[][72], index1, index2);
Blob(arr[22][72], index1, index2);

和函数定义参数:

void Blob(char c[ONE_D][TWO_D], int row, int col)

Answer 1

问题是您正在声明一个名为 blob(char **, int, int) 的函数，然后将该声明更改为 blob(char **c[ONE_D ][TWO_D], int, int).

鉴于您确实将 char **arr 传递给函数，我建议您删除 [ONE_D][TWO_D] 部分，因为那是本质上是让你的函数接受一个 4 维数组 [或者一个指向二维数组的指针，可能]。

您还需要将 **c[...][...] 更改为 c[...][...]。