C++ 2D array from read text file

Question

I'm trying to put a 15x15 maze from a text file into a 2D array. So far, it's printing out a really stranger version so the maze looks weird and I can't move around a character.

static const int WIDTH = 15;
static const int HEIGHT = 15;

//declared an array to read and store the maze
char mazeArray[HEIGHT][WIDTH];

ifstream fin;
     fin.open("lvl1.txt");

        char ch;

        while (!fin.eof())
         {
           fin.get(ch);
            for(int i=0 ; i < HEIGHT ; i++)
              {
                for(int j=0 ; j < WIDTH ; j++)
                {
                 fin >> mazeArray[i][j];
                 cout << ch;
                } 
             }
        }
     fin.close(); 

# # # # # # # # # # # # # # # 
#             # # # # # # # #
# # # # #   # # #   # # # # # 
# #   # #   # # #   #   # # # 
# #   # #   #       #   # # # 
# #   # #   # #     #   # # # 
# #         # #   # #   # # # 
# #   # #   #     # #   # # # 
# #   # #   #     # #     O #
# #   # #   #     # #   # # # 
# #   # #   #     # #   # # # 
# #   # #   #     # #   # # # 
# #                     # # # 
# #   # # # # # #       # # # 
# # # # # # # # # # # # # # #

Above is a function which is supposed to read the file and place into a 2D array so I can call it later. Below it is the maze i'm trying to read out. Any ideas on why it's printing out wrong?

Search the internet for "stackoverflow c++ read file matrix" — Thomas Matthews, Mar 08 '17 at 03:16
Why are you printing `ch` over and over again without giving it a new value? What value do you expect? Is that the actual maze you're reading, and are those spaces in the file? Are you familiar with the idea of a [minimal complete example](http://stackoverflow.com/help/mcve)? — Beta, Mar 08 '17 at 03:16
while not eof is bad: http://stackoverflow.com/questions/5605125/why-is-iostreameof-inside-a-loop-condition-considered-wrong — user4581301, Mar 08 '17 at 03:53

Anderson · Answer 1 · 2017-03-08T20:43:12.593

This should work..

#include <iostream>
#include <fstream>
#include <string>
#include <algorithm>

const int R = 15, C = 15;

char** createMatrix(char* fileName)
{
    char** c_matrix = nullptr;
    std::string s = "";
    std::fstream file (fileName);   

    c_matrix = new char*[R];
    for (int r = 0; r != R; ++r)
    {
        int cc = 0;
        c_matrix[r] = new char[C];
        std::getline(file, s);
        for (int c = 0; c != C*2; c += 2)
        {
            c_matrix[r][cc] = s.at(c);
            ++cc;

        }
    }

    file.close();
    return c_matrix;
}

void printMatrix (char** matrix)
{
    for (int r = 0; r != R; ++r)
    {
        for (int c = 0; c != C; ++c)
        {
            std::cout << matrix[r][c] << " ";
            if (c == 14)
            {
                std::cout << std::endl;
            }
        }
    }
}

int main()
{

    char** matrix = createMatrix("matrix.txt");
    printMatrix(matrix);

    return 0;
}

Output:

# # # # # # # # # # # # # # # 
#             # # # # # # # #
# # # # #   # # #   # # # # # 
# #   # #   # # #   #   # # # 
# #   # #   #       #   # # # 
# #   # #   # #     #   # # # 
# #         # #   # #   # # # 
# #   # #   #     # #   # # # 
# #   # #   #     # #     O #
# #   # #   #     # #   # # # 
# #   # #   #     # #   # # # 
# #   # #   #     # #   # # # 
# #                     # # # 
# #   # # # # # #       # # # 
# # # # # # # # # # # # # # #

C++ 2D array from read text file

1 Answers1