Thread: ANSI C ASCII String to HEX byte array conversion

doesn't really look like you want to convert the string. looks more like you want to preface each hex number with a 'x'.

in any case you'll have to create a new string long enough to hold the 'x' character and that '\'.
then you need to iterate over buf and copy its contents to the new string. placing your 'x' and '\' characters and their respective indexes.

this may not be what you want, but that's what you asked.

>char buf[] = "9EF4BCDE";
>to an array of Hexidecimal bytes, equivalent to say:
>char buf[] = "\x9e\xf4\xbc\xde";

Code:

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

void to_hex(char buf[], int i)
{
  if (*buf == '\0')
    return;

  to_hex(buf + 2, i + 1);
  buf[1] = strtol(buf, NULL, 16);
  *buf = '\0';
}

int main(void)
{
  char buf[] = "9EF4BCDE";
  int i;

  to_hex(buf, 0);

  for (i = 1; buf[i] != '\0'; i += 2)
    printf("%#x\n", (unsigned char)buf[i]);

  return 0;
}

Aww... come one caroundw5h - you should know by now that \x looks an awful lot like an escape sequence! As such, it would only take up on element in a char array.

you are right of course, thus my repsonse

doesn't really look like you want to convert the string. looks more like you want to preface each hex number with a 'x'.

I suppose my second paragraph was a little misleading. My apologies to the OP.

>that is exactly what I want
God, I hope not. I went out of my way to avoid using a second buffer. Though a two-step process could solve the problem of holes in the array by performing the conversion and then compacting the even elements.

>With a few minor tweaks
Yes, I imagined that tweaks would be needed.

>I will post the completed project tommorow for critique
Yay! Code review! (See my new avatar and read that again )

>What exactly is your new avatar?
Probably the cutest anime cat I've ever seen. I don't know where from though, I found it while net diving a few weeks ago.

>Uhmmm... I'm gonna have to go with your old one on that....

haha I think they are both about the same.

And as for the solution to the problem, when I read the title I thoguht you wanted what Prelude suggested, then I read your post. At that point I was a bit confused.

Anyway I think I know what the cat is from, but I will need to double check on it. I'll get back to you on it if I'm right.

[edit]
Update: no idea where your avatar is from.
[/edit]