Multidimensional array with unknown items - c

Question

#include <stdio.h>
#include <stdlib.h>
int main() {
int *width;
int *height;
int row;
int column;
int character;
int count;
int pictureit;
double i = 0;
FILE *fp;
char file[50];
char line[25]; // assume each line has max 25 characters
printf("What file should we pull from: ");
scanf("%s", file);
//read file using File pointer
fp = fopen(file, "r");
// read the first line in the file
fgets(line, sizeof(line), fp);
width = strtok(line,"x");
height = strtok(NULL, "/0");
// read all the future lines in the file excluding the first
while (fgets(line, sizeof(line), fp)) {
row = strtok(line, ",");
column = strtok(NULL, ",");
character = strtok(NULL, ",");
count = strtok(NULL, "/0");
if(i < count) {
**printf("%s", pictureit[row][column] = character);**
i++;
}
}
fclose(fp);
return 0;
}
I'm pulling in a file with this kind of setup
75x53
0,36,.,1
0,37,M,1
1,32,.,1
1,33,:,1
1,34,A,1
1,35,M,2
1,37,O,1
1,38,:,1
2,23,.,1
2,24,:,1
2,25,A,1
2,26,M,5
I've been brainstorming for a while. How would I go about displaying this on the console? It obviously needs to go into a 2d array. The program needs to know the height and width of the array to display a space or character in that spot.
PS: This program will display a picture in the console when finished. The "** **" is where I am working.

Answer 1

You could dynamically allocate a 2d array with the right dimensions (according to your first line), then fill it up with the data from your file and finally print it with two nested for loops.
EDIT: Basically, you would do:
//...
//Create the dynamic array
char ** array = malloc(sizeof(char) * height);
int i;
for(i = 0; i < height; i++)
array[i] = malloc(sizeof(char) * width);
// Fill your array here (put different chars in it) ...
//Print it
int x,y;
for(y = 0; y < height; y++)
{
for(x = 0; x < width; x++)
printf("%c ", array[y][x]);
printf("\n");
}
//Free the array
for(i = 0; i < height; i++)
free(array[i]);
free(array);
I voluntarily omitted the part where you check the return value of the malloc (whether it's NULL or not), but you should definitely add it.

Answer 2

Normally I wouldn't do this, but I felt the need to do a scanning exercise:
int main(void)
{
char fn[100];
fprintf(stdout, "Enter file name:");
fflush(stdout);
int result = fscanf(stdin, " %99s", fn);
if (1 != result)
{
fprintf(stderr, "Reading the file's name failed.\n");
exit(EXIT_FAILURE);
}
{
size_t width= 0;
size_t height 0;
FILE * pf = fopen(fn, "r");
if (NULL == pf)
{
fprintf(stderr, "Opening file '%s' failed.\n", fn);
exit(EXIT_FAILURE);
}
{
result = fscanf(pf, " %zux%zu", &width, &height);
if (2 != result)
{
fprintf(stderr, "Reading width and/or heigth from file '%s' failed.\n", fn);
exit(EXIT_FAILURE);
}
{
char (*pa)[width][height] = calloc(1, sizeof *pa);
if (NULL == pa)
{
perror("calloc() failed");
exit(EXIT_FAILURE);
}
{
size_t number_of_rows = width * height;
fprintf(stderr, "Trying to read %zu data rows.\n", number_of_rows);
for (size_t row = 0; row < number_of_rows; ++row)
{
size_t x, y;
char c;
int i;
result = fscanf(pf, " %zu,%zu,%c,%d", &x, &y, &c, &i);
if (4 != result)
{
fprintf(stderr, "Reading data (#%zu) row from '%s' failed.\n", row, fn);
exit(EXIT_FAILURE);
}
/* Add check here to avoid accessing the array out-of-bounds! */
(*pa)[x][y] = c;
}
}
{
for (size_t row = 0; row < width; ++row)
{
for (size_t column = 0; column < height; ++column)
{
fprintf(stdout, "%c", (*pa)[row][column]);
}
fprintf(stdout, "\n");
}
}
free(pa);
}
}
fclose(pf);
}
return EXIT_SUCCESS;
}
Also I am curious about the picture to be printed ... ;-)