在c中将矩阵文本文件读入数组

Question

I have started learning to code in C, and I am stuck at a assignment where I'm supposed to read a file, put the contents in a matrix, and finally print the matrix.

The input file contains:

    ------01-1
    1--------1
    --0-1-----
    ----0-----
    ------0--1
    -----1--1-
    ------0--0
    0---------
    --11-----1
    0-1-----0-

This is the code that I have written so far:

int main()
{   
    FILE *filename = fopen("file.txt","r");
    int matrix[10][10];
    int c;

    for(int i =0; i < 10; i++)
    {
        for(int j=0; j<10; j++)
        {
            c = fgetc(filename);
            if(c == '1')
            {
                matrix[i][j] = 1;
            }
            else if(c == '0')
            {
                matrix[i][j] = 0;
            }
        }
    }

    for(int a = 0; a < 10; a++)
    {
        for(int  b = 0; b < 10; b++)
        {
            printf("%d", matrix[a][b]);
        }
        printf("\n");
    }

}

the output:

-520092443803-520092443-12480181
2686620131463841127199806539638031616085
1316435226866683164344001-520092443011
51119868016113146336314633624404833019927382943080192
26869241998418816-1123324798-2268660019980688424308334426866161992765860
0019927658711830833442686648199276586030801920
1-8756571168119980461561998099927-13626866284
0175821461101992769785308335604200816026866681992735205
199343520826867321992749998819927700401992769850-875656752419907241990720
11268674426869241992847904-1121896548-2119927710210

Press any key to continue.

My guess with the output is that it doesn't add the c value into the matrix. So it prints a "empty" array; the empty array leads to weird numbers?

I know that I'm reading characters from the text file. So I need to convert them to int values.

But why does my code go wrong and where does it go wrong?

Answer 1

Initialize the matrix

int matrix[10][10] = {0};

Handle input other than 0 and 1

What else do we need to handle:

1. Hyphen or - input: Save some other number for ex: 2 or -1
2. EOF or end of file: End the program or similar handling
3. New line, trailing space or other unknown character: Ignore the character and read again

c = fgetc(filename);
if(c == '1')
{
   matrix[i][j] = 1;
}
else if(c == '0')
{
    matrix[i][j] = 0;
}
else if(c == '-')
{
    matrix[i][j] = -1;  /* Special number for - */
}
else if(c == EOF)
{
    return -1; /* End of file handling */
}
else
{
   --j; /* Ignore this character and enter into loop again */
   /* Although modifying loop controlling var inside is not a good habit */
   /* For this small module, it should be fine */
}