Thread: Chopping up a string

I'm a newbie, so please be nice to me ;-)

I've been programming in C for about a month now, but I haven't really done alot. I'm trying to write one of those simple XOR encryption programs.

I want to open a text file, read form it charcter by charcter
encrypt each line
write the number to a a file

then

read file line by line
decrypt each line
write decrypted file

I have no problems encrypting the file, it is decrypting thats my problem. I'm using spaces to separate each charcater, and I have no clue how to make the string of numbers into intergers.

I hope thats clear enough... If you have any questions let me know. Thank you!

Here is a piece of the code...

Code:

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "encfunc.h"
#include "fexist.h"

void enc_file(void)
{
  char buffer[256];
  int key = 99;
  int count = 0;
  int enc = 0;
  FILE *in, *out;

  if ((in = fopen("in.txt", "r")) == NULL)
    {
      fprintf(stderr, "Error opening file!");
      exit(EXIT_FAILURE);
    }

  if ((out = fopen("out.txt", "w")) == NULL)
    {
      fprintf(stderr, "Error opening file!");
      exit(EXIT_FAILURE);
    }

  while (1) {
    enc = fgetc(in);

      if (!feof(in))
	{
	  enc = enc ^ key;
	  fprintf(out, "%d ", enc);
	}
      else
	break;
  }

  fclose(in);
  fclose(out);
}

void denc_file(void)
{
  char buffer[256];
  int key = 99;
  int tmp = 0;
  int enc = 0;
  int len = 0;
  FILE *fp;

  if ((fp = fopen("test.txt", "r")) == NULL)
    {
      fprintf(stderr, "Error opening file!");
      exit(EXIT_FAILURE);
    }

  fclose(fp);
}

If this is encode
enc = enc ^ key;
fprintf(out, "%d ", enc);


This would be decode
fscanf(in, "%d ", &enc);
enc = enc ^ key;

Thank you so much, Salem
I was totatly clueless. I wish I had some friends that knew C. I'm 15 y/o, and none of my freinds are into programming.

Originally posted by Bubba
Well now you do. You've got us and we are all into programming.

Awww, you guys are great. I've always been impressed at how people on message boards are so willing to help newbies. I honestly am very thankfil for people who are willing to help newbies with the stupidest problems

Enough of my mushy stuff Thanks everyone!

Originally posted by Salem
If this is encode
enc = enc ^ key;
fprintf(out, "%d ", enc);


This would be decode
fscanf(in, "%d ", &enc);
enc = enc ^ key;

...and don't forget that sometimes enc == key...