// rewind example 
// source: http://www.cplusplus.com/

#include <stdio.h>
#include <stdlib.h>

int main()
{
  int n;
  FILE *pFile;
  // 26 chars for the alphabet + NUL character ('\0') to terminate the string
  // checkout http://www.asciitable.com/ for assic table -- NUL is `\0` is 0
  // BTW, we use NUL (one L) to refer to terminating a string, and NULL for
  // pointers -- NULL pointer. 
  char buffer[27]; 

  pFile = fopen("myfile.txt", "w+");
  for (n = 'A'; n <= 'Z'; n++)
    fputc(n, pFile);

  rewind(pFile);
  fread(buffer, 1, 26, pFile);
  fclose(pFile);

  // note, once the data is read into a char array (string)
  // a NULL is added to the end to terminate the string.
  // try commenting out the line below and see what happens
  // Result: it might work or get segfault.
  buffer[26]='\0';

  // Create a bug and uncomment the line below. Maybe the result
  // is a segfault of the puts() runs on until it finds a 0. 
  // try and work it out.
  // buffer[26]='a';
  puts(buffer);

  return 0;
}