Help with reading/writing integers in a specific way into/from a file!!

Hi!
I am trying to learn how to read and write integers into a file in severreral rows.
Then I want to read the Integers from each row and put the integers in separate arrays.

Example of how the file looks like after adding integers:
=======================================
1 2 3 4 5...
6 5 4 3 2...
7 78 5 45...


How do I write to put maybe 100 integers in the first row, then the second row and so on???
When I have managed hat I want to read the integers from the first row and put them in a array like this:
[1][2][3][4][5] without the space betwwen each integer!
Here I also don't now how I start reading the integers from the second row to put the integers in another array.

So far I have tested to put 2 integers in the first row. Is it necessary to fprintf a space after each integer or is there another way??

int main(int argc, char *argv[])
{
FILE *myFile = fopen("txtFile.txt", "w");

fprintf(myFile, "13");
fprintf(myFile, " ");
fprintf(myFile, "4\n");
fclose(myFile);

system("PAUSE");
return 0;
}

Appreciate any help!

PS, how do I align the code so it gets nicer?? THe link from the faq is dead.

[code]/*code goes here */[/code]

Code:

---

#include <stdio.h>

#define SIZE 5

int main(void)
{
  int i, j, array[3][SIZE];
  /*
    * Write numbers to a file.
    */
  FILE *file = fopen("file.txt", "w");
  if ( file )
  {
      /* write as many number as the entire array will hold */
      for ( i = 0; i < sizeof(array)/sizeof(**array); ++i )
      {
        /* Write numbers to file, 'SIZE' per line. */
        j = i + 1;
        fprintf(file, "%d%c", j, (i % SIZE) == (SIZE - 1) ? '\n' : ' ');
      }
      fclose(file);
  }
  /*
    * Read numbers from file.
    */
  file = fopen("file.txt", "r");
  if ( file )
  {
      /* 'i' is the "row" */
      for ( i = 0; i < sizeof(array)/sizeof(*array); ++i )
      {
        /* 'j' is the "column" */
        for ( j = 0; j < sizeof(*array)/sizeof(**array); ++j )
        {
            /* read the next whitespace-separated number */
            if ( fscanf(file, "%d", &array[i][j]) != 1 )
            {
              goto end; /* failed or reached end of file */
            }
            printf("array[%d][%d] = %d\n", i, j, array[i][j]);
        }
      }
      end:
      fclose(file);
  }
  return 0;
}

/* file.txt
1 2 3 4 5
6 7 8 9 10
11 12 13 14 15
*/

/* my output
array[0][0] = 1
array[0][1] = 2
array[0][2] = 3
array[0][3] = 4
array[0][4] = 5
array[1][0] = 6
array[1][1] = 7
array[1][2] = 8
array[1][3] = 9
array[1][4] = 10
array[2][0] = 11
array[2][1] = 12
array[2][2] = 13
array[2][3] = 14
array[2][4] = 15
*/

---

[edit]
Added comments.
[/edit]

Thanks for the example. It looks a bit difficult in some parts.
Let me explain a bit easier.
Maybe I want to write integers from 1 to 10 in the first row with a loop.
THen in another loop I want to add 10 random numbers with
rand() in the second row.

Then I want to only read the integers from the first row and put them in an array.
Or I only want to read the Integers from the second row and put them in an array.

How to I start adding new integers in the second row, third row and so on or reading from the second row until I reach \n in each row???

Quote:

---

fprintf(file, "%d%c", j, (i % SIZE) == (SIZE - 1) ? '\n' : ' ');

---

This is a bit hard to understand

/**/

Quote:

---

Code:

---

fprintf(file, "%d%c", j, (i % SIZE) == (SIZE - 1) ? '\n' : ' ');

---

---

Since SIZE is 5 in this example, the last parameter reduces to

Code:

---

(i % 5) == 4 ? '\n' : ' '

---

For i == 0, i % 5 == 0, so a space goes with the %c.
For i == 1, i % 5 == 1, so a space goes with the %c.
...
For i == 4, i % 5 == 4, so a newline goes with the %c.
For i == 5, i % 5 == 0, so a space goes with the %c.
...

Quote:

---

Maybe I want to write integers from 1 to 10 in the first row with a loop.
THen in another loop I want to add 10 random numbers with
rand() in the second row.

---

Maybe I'll just write some numbers in a file to make the example simple.

Quote:

---

Then I want to only read the integers from the first row and put them in an array.
Or I only want to read the Integers from the second row and put them in an array.

---

Here's one way.

Code:

---

#include <stdio.h>

int gimme(const char *filename, int row, int *array, size_t size)
{
  FILE *file = fopen(filename, "r");
  if ( file )
  {
      size_t i;
      while ( row-- )
      {
        for ( i = 0; i < size; ++i )
        {
            fscanf(file, "%d", &array[i]);
        }
      }
      for ( i = 0; i < size; ++i )
      {
        printf("%d,", array[i]);
      }
      putchar('\n');
      fclose(file);
  }
}

int main(void)
{
  int array[5];
  gimme("file.txt", 1, array, sizeof(array)/sizeof(*array));
  gimme("file.txt", 3, array, sizeof(array)/sizeof(*array));
  gimme("file.txt", 2, array, sizeof(array)/sizeof(*array));
  return 0;
}

/* file.txt
1 2 3 4 5
6 7 8 9 10
11 12 13 14 15
*/

/* my output
1,2,3,4,5,
11,12,13,14,15,
6,7,8,9,10,
*/

---

Jeez!! Here's the code that newbie's should understand

Code:

---

#define MAXVALPERLINE 10
...
for (i=0; i < MAXVALPERLINE; i++)
{
    fprintf(file, "%d ", i);
}
fprintf(file, "\n");

for (i=0; i < MAXVALPERLINE; i++)
{
    fprintf(file, "%d ", (int)(rand()*x));
}
fprintf(file, "\n");

---

Quote:

---

fprintf(file, "%d%c", j, (i % SIZE) == (SIZE - 1) ? '\n' : ' ');

---

I've never used anything that convoluted in 20 years of C programming. Sorry Dave, it's cool and all but....