?
Solved

Hex to Ascii/Integer

Posted on 1998-05-20
5
Medium Priority
?
1,457 Views
Last Modified: 2012-05-04
(C on Solaris 2.x)
Hi,
I'm having problems on how to store some Hex values.
Hopefully you can help this newbie in C.

First of all, here're 2 simple variables I'm having ...

      unsigned char *source, *dest;

After I read in a string e.g. "12AB" into source, I convert the string into Hex and put the output into dest :

        < ..read string "12AB" from file into source ...>          
          AsciiToHex(source, strlen(source), dest);
          dest[2]='\0';

Now the problem is I need to store the decimal value of hex '12' (which is 1x16 + 2 = 18) and similarly that of 'AB' (which is 10x16+11=171) into 2 separate ascii strings :

           unsigned char *var1, *var2;

so that var1 contains "18" and var2 has "171" in ascii.

How do I do that ?

Thanks for helping !!!!!
0
Comment
Question by:totoro030898
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
  • 2
5 Comments
 

Author Comment

by:totoro030898
ID: 1250869
Edited text of question
0
 
LVL 84

Expert Comment

by:ozo
ID: 1250870
Where do you allocate storage fot *dest?

unsigned char *source, *dest;
unsigned char *var1, *var2;
source=strdup("12AB");
dest=malloc((strlen(source)+3)/2);
AsciiToHex(source, strlen(source), dest);
var1=malloc(4);
var2=malloc(4);
sprintf(var1,"%d",dest[0]);
sprintf(var2,"%d",dest[1]);
0
 
LVL 11

Accepted Solution

by:
alexo earned 600 total points
ID: 1250871
#include <string.h>

unsigned char xlate(char ch)
{
    if (ch >= '0' && ch <= '9')
        return ch - '0';
    else if (ch >= 'A' && ch <= 'F')
        return ch - 'A' + 10;
    else if (ch >= 'a' && ch <= 'f')
        return ch - 'a' + 10;
    else /* Error */
        return 0;
}

void AsciiToHex(char* src, int len, char* dest)
{
    if (len & 1) /* Odd length */
    {
        *dest++ = xlate(*src++);
        len--;
    }

    while (len)
    {
        *dest++ = xlate(*src++) * 16 + xlate(*src++);
        len -= 2;
    }

    *dest = '\0';
}

void main()
{
    char from[] = "12A";
    char to[3];

    AsciiToHex(from, strlen(from), to);
}

0
 

Author Comment

by:totoro030898
ID: 1250872
As a newbie to C, personally think that ozo's answer is short and simpler. however still thanks to alexo! i did learn something!
0
 
LVL 11

Expert Comment

by:alexo
ID: 1250873
I gave you an implementation of AsciiToHex(), ozo gave you a way to use one.  Two different things.
0

Featured Post

Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Windows programmers of the C/C++ variety, how many of you realise that since Window 9x Microsoft has been lying to you about what constitutes Unicode (http://en.wikipedia.org/wiki/Unicode)? They will have you believe that Unicode requires you to use…
Examines three attack vectors, specifically, the different types of malware used in malicious attacks, web application attacks, and finally, network based attacks.  Concludes by examining the means of securing and protecting critical systems and inf…
The goal of this video is to provide viewers with basic examples to understand and use structures in the C programming language.
Video by: Grant
The goal of this video is to provide viewers with basic examples to understand and use for-loops in the C programming language.
Suggested Courses

771 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question