C programming: Read (double) numbers from text file, line by line to a 2D array

Question

I have a text file created with excel that contains a table of dimensions 36x35. The values are double numbers (eg 2.58) and the text file looks like this:

1.25  2.31 ...
4.28  2.56 ...
3.27  ...
...   ...

I know the dimensions of the table (arr_row, arr_column) so declare a dynamic 2D array:

double **MUDG_table;

//dynamic allocate array of MUDG_table (1st Dimension)
MUDG_table = calloc(arr_row,sizeof(int *));

//check if the memory has been allocated correctly
if (MUDG_table==NULL) 
{
    printf("Error allocating memory!\n"); //print an error message
    return 1; //return with failure
}

for (cv02=0;cv02<arr_row;cv02++)
{
    //dynamic allocate array of MUDG_table (2nd Dimension)
    MUDG_table[cv02] = calloc(arr_column, sizeof(int));

    //check if the memory has been allocated correctly
    if (MUDG_table[cv02]==NULL) 
    {
        printf("Error allocating memory!\n"); //print an error message
        return 1; //return with failure
    }
}

So far so good. Then I try to read the values from the text file and store them to the array for further processing:

//************************************************************************************************************//
//read the text file with the values of the gain and save it to the MUDG_table
//************************************************************************************************************//

gain_ptr = fopen("MUDG_text.txt", "r");

if (gain_ptr == NULL)
{
    printf("Error Reading File\n");
    return 1; //return with failure
}

for (row=0;row<arr_row;row++)
{
    for (column=0;column<arr_column;column++)
    {
        fscanf(gain_ptr, " %1f", &MUDG_table[row][column]);
    }
}

fclose(gain_ptr);

and the problem is that the values I get are something like 5.26346e-315#DEN Any ideas what I am doing wrong. Is it because I do not use the EOF?

Answer 1

OK, so after going through several posts and thanks to the responses I got here, I changed the code and it seams to work properly.

First of all the array should be declared as double:

//dynamic allocate array of MUDG_table (1st Dimension)
MUDG_table = calloc(arr_row,sizeof(double *));

//check if the memory has been allocated correctly
if (MUDG_table==NULL) 
{
    printf("Error allocating memory!\n"); //print an error message
    return 1; //return with failure
}

for (cv02=0;cv02<arr_row;cv02++)
{
    MUDG_table[cv02] = calloc(arr_column, sizeof(double));

    //check if the memory has been allocated correctly
    if (MUDG_table[cv02]==NULL) 
    {
        printf("Error allocating memory!\n"); //print an error message
        return 1; //return with failure
    }
}

The main problem was the fscanf which I have no idea why it is not working. So I replaced it with the fgets. I found this code in another post and I modified it to work in this case.

gain_ptr = fopen("MUDG_text.txt", "r");

if (gain_ptr == NULL)
{
    printf("Error Reading File\n");
    return 1; //return with failure
}

for (row=0;row<arr_row;row++)
{
    fgets(buffer, 1024, gain_ptr); //buffer is declared as char buffer[1024];

    tok = strtok(buffer, "\t");    // NULL means 'continue from last token'  
    //tok is declared as char *tok;
    //the numbers in my text file are seperated by tabs
    //so the tokens should be separated by \t

    column = 0;  //since fgets gets a whole line I had to separate the columns
    while (tok != NULL) 
    {
        test_var = atof(tok);  //test variable is declared as double
        //and it is used to hold temporarily the value of tok in double
        tok = strtok(NULL, "\t");    // NULL means 'continue from last token'

        MUDG_table[row][column] = test_var;
        column++;
    }
}   
fclose(gain_ptr);

Maybe it is not the best solution, but at least it works.