Being concise, I want to read a file and store the content in a 2D array, where the first dimension refers to the line and the second dimension to the character in the respective line. I do not know the number of lines and columns on each line beforehand.
The code I tried is as follows.
P.S.: I know the variables's names are not that good XD
FILE *filepointer = fopen(commandlineargument.filtersfile, "r");
int numboflines = 0;
int numbofchars = 0;
char **array = malloc(numboflines + 1);
array[0] = malloc(numbofchars + 1);
char currentchar;
while(fscanf(filepointer, "%c", ¤tchar) != EOF)
{
if(currentchar != '\n')
{
array[numboflines][numbofchars] = currentchar;
numbofchars++;
array[numboflines] = realloc(array[numboflines], numbofchars + 1);
}
else
{
array[numboflines][numbofchars] = '\0';
numbofchars = 0;
numboflines++;
array = realloc(array, numboflines + 1);
}
}
array[numboflines] = '\0';
numboflines--;
With the code above, I can just get the value of array[0][0] and only before it gets reallocated two lines down (then array[0][0] points to null). I get Segmentation Fault later.
P.S.: I know the code above will only work properly if the last line ends with a \n
An example of the desired output:
File Content:
>Abcde
fghijk
>Lmno
pq
2D Array values:
array[0][0] = ">"
array[2][1] = "L"
And so on.
Your code is fine, but it has one omission and one mistake:
The mistake: memory space for each element of array is not a character, but a pointer to a character, so this line:
char **array = malloc(numboflines + 1);
should be rewritten as this:
char **array = malloc((numboflines + 1)*(sizeof *array));
The omission: after you end a line and realloc array, you must malloc the newly array element:
numboflines++;
array = realloc(array, numboflines + 1);
Becomes:
numboflines++;
array = realloc(array, (numboflines + 1)*(sizeof *array));
array[numboflines] = malloc(numbofchars + 1);
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