C: how to store into a int array each line of a text file with different size?

Question

I need to read a file and store at each time step each line (int) in a array of integers and then work in this array.

The input looks like this:

0 16 12

1 10 17

2 14 8

3 12 17 16

9 14 16 19 13 5

19 16 6 17 11 15 9 4 12 18 8

Then using something like this I can read and print each lines but I can not save each line in an array per time.

char matrix[500][500], space;
int numbers[500], i = 0, j;
int elementsA[10000];
FILE *fp = fopen("mygraph", "r");
int blabla[1000000];
int a;

while(!feof(fp))
{
    fscanf(fp, "%d", &numbers[i]); // getting the number at the beggining
    fscanf(fp, "%c", &space); // getting the empty space after the number
    fgets(matrix[i++], 500, fp); //getting the string after a number        
    a ++;
}
for(j = 0; j < i; j++)
    printf("%d %s %d\n", numbers[j], matrix[j]);



return(0);

}

Thanks everybody for helping me.

Answer 1

One possible approach uses these steps:

1) get a file pointer: FILE *fp = fopen("c:\\dir1\\file.txt", "r");
2) use fgets() in two ways:
first to count number of lines in file, and get longest line (hint: count spaces for number of ints)
(with this information, you can create and allocate memory for a 2D int array)
second restart from beginning to read one line at a time.
3) use strtok() (or strtok_r()) to parse each line into integers and place into your array
4) free all memory and exit.

Here is a way to get the information to allocate your arrays:
Give the input (each line must contain a \n, as this one does):

0 16 12
1 10 17
2 14 8
3 12 17 16
9 14 16 19 13 5
19 16 6 17 11 15 9 4 12 18 8  

The following code will provide number of lines and highest number of ints/line in file,
Then create your array:

int GetParamsOfFile(char *path, int *numInts) ;

int main(void)
{
    int lines;
    int mostInts;
    int **array=0;
    lines = GetParamsOfFile("place your path here", &mostInts);
    //                      rows   columns (will correlate with rows and column of your file)
    array = Create2D(array, lines, mostInts);//creates array with correct number of rows and columms;
    //Here is where you would re-read your file, this time, populating your new array.  
    //I will leave this part to you... 
    free2DInt(array, mostInts);
    return 0;
}

int GetParamsOfFile(char *path, int *numInts)
{
    FILE *fp = fopen(path, "r");
    int spaces=0, lines=0, sK=0;
    char *line;  //choose big here
    char *buf;
    line = malloc(1000);
    line = fgets(line, 1000, fp);
    while(line)
    {
        lines++;
        spaces = 0;
        buf = strtok(line, " ");
        while(buf)
        {
            spaces++;
            buf = strtok(NULL, " ");
        }
        (spaces > sK)?(sK = spaces):(sK==sK);
        line = fgets(line, 1000, fp);
    }
    *numInts = sK;
    fclose(fp);
    free(line);
    return lines;
}

int ** Create2D(int **arr, int rows, int cols)
{   
    int space = cols*rows; 
    int    y;

    arr   = calloc(space, sizeof(int));
    for(y=0;y<rows;y++)
    {
        arr[y] = calloc(cols, sizeof(int)); 
    }
    return arr;
}

void free2DInt(int **arr, int rows)
{
    int i;
    for(i=0;i<rows; i++)
        if(arr[i]) free(arr[i]);
    free(arr);  
}

Answer 2

#include <stdio.h>
#include <ctype.h>

int countitems(char * s) {
  int i;

  for (i=0; *s; i++) {
    while (*s && isblank(*s++));
    while (*s && !isblank(*s++));    
  }
  return(i);
}

char * nextitem(char *s) {
  while (*s && !isblank(*s)) s++;
  while (*s && isblank(*s)) s++;
  return (s);
}

char * skipblanks(char *s) {
  while (*s && isblank(*s)) s++;

  return (s);
}

int main() {
  FILE *f;
  int i, j;
  char s[100];
  char * ss;

  f = fopen("mygraph.txt", "r");
  i = 0;
  while (!feof(f)) {
    fgets(s, 99, f);
    j = countitems(s);
    if (j>i) i = j;
  }
  printf("you need %d columns\n", i);
  // allocate matrix
  rewind(f); // at leat once in a life...rewind!!
  while(!feof(f)) {
    fgets(s, 99, f);
    ss = skipblanks(s);
    while (*ss) {
      sscanf(ss, "%d", &j);
      printf("%d ", j); // do something with numbers
      ss = nextitem(ss);
    }
    printf("\n");
  }
  fclose(f);
}