storing text file contents into a string

I've wrote a program that takes a text file in as a string, and encrypts it, using my own, very weak, encryption key. The program works, as long as the text file contains only a single word, with no spaces. I'm assuming for some reason it doesn't like spaces. My code is as follows

Code:

---

#include <stdio.h>
#include <string.h>


int main (int argc, char *argv[])
{
  FILE *in;
  FILE *out;
  char buf[512];
  char secret[512];
  int x;
 
  in = fopen ( argv[1], "r" );
  out = fopen (argv[2], "w+" );

  if ( in == NULL ) {
    perror ( "Unable to open the file" );
  }

  /* Read a string */
  fread ( buf, 1, sizeof buf, in );
  printf ( "%s\n", buf );

  /*pre programm processesing and beautifying*/
  system("clear");
  printf("\n\n");


  for (x = 0; x < 512; x++) { //begin for loop
  switch(buf[x])
  {  //begin switch/case
 
  // encryption key hidden for security reasons

  }  //end switch/case
  }  //end for loop



  fprintf(out, "%s\n", secret); 
  fclose ( in );
  fclose (out);


  printf("%s\n", secret);



  printf("\n\n");
} //end main

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If anyone could recommend any modifications, I'd appreciate it.
Michael

Ahh, you have to love security by obscurity. I don't see why it would only handle single words with the code you've shown. Are you sure your encryption isn't changing a space into '\0'?

When you print the string right after reading it does it print the whole string or only 1 word? Please explain what you mean by "it only works when it's 1 word".

And also:

Code:

---

for (x = 0; x < 512; x++) { //begin for loop

---

Gee, ya think? ;)

ok, by "it only works with one word", i mean, if i use a line of text that includes a space, the text file created by the program, is completely empty.

ok, i have that part figured out, but now i have a new question. When I store the text file into a string, I think that setting the string to 512 bytes, it automatically fills in the rest of the 512 bytes if the text file does not fill the buffer. Is there a way to do a SIZEOF file.txt? or something to that end?

Why not use the return value of fread()? It tells you how many items it read.
You could do:

Code:

---

{
  size_t data_len;

  data_len = fread ( buf, 1, sizeof buf, in );
}

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