La misma pregunta en FILE!

FILE *fp;
  int i;
  
  fp = fopen("C:\My Documents\book\seats.db", "w");
  if(fp == NULL)
  {
    printf("Can't create file: Data\seats.db");
    exit(0);
  }
  else
  {
    for(i = 0; i < 8; i++)
    {
      fprintf(fp, "XXXXXXXX");
      if(i != 7)
      {
        fprintf(fp, "\n");
      }
    }    
    fclose(fp);
   
  }
}

#include <stdio.h>

#define SEATS_DATABASE "seats.db"
#define NUM_ROWS    8
#define NUM_SEATS   8

void initDataBase(void)
{
  FILE *fp;
  int i;
  int j;

  fp = fopen(SEATS_DATABASE, "w");
  if(fp == NULL)
  {
    printf("Can't create file");
    exit(0);
  }
  else
  {
    for(i=0; i<NUM_ROWS; ++i)
    {
      for(j=0; j<NUM_SEATS; ++j)
        fputc('X', fp);
      if(i != NUM_ROWS-1)
        fputc(10, fp);
    }
    fclose(fp);
  }
}

void changeSeat(int row, int seat, char ch)
{
  FILE* fp;

  fp = fopen(SEATS_DATABASE, "r+");
  if (fp)
  {
    fseek(fp, row*(NUM_SEATS+1)+seat, SEEK_SET);
    fputc(ch, fp);
    fclose(fp);
  }
  else
  {
    printf("Can't update the database\n");
  }
}

int main(void)
{
  initDataBase();

  changeSeat(3, 3, 'O');
  changeSeat(0, 1, 'O');

  return 0;
}