Solved

Hex to Ascii/Integer

Posted on 1998-05-20
5
1,450 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
  • 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 200 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

Three Reasons Why Backup is Strategic

Backup is strategic to your business because your data is strategic to your business. Without backup, your business will fail. This white paper explains why it is vital for you to design and immediately execute a backup strategy to protect 100 percent of your data.

Question has a verified solution.

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

Suggested Solutions

Title # Comments Views Activity
How to organize data in excel ? 2 115
negation in C function 14 161
Can case within switch statement specify range of values ? 3 87
Why is compiler in oracle server ? 9 75
Have you thought about creating an iPhone application (app), but didn't even know where to get started? Here's how: ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ Important pre-programming comments: I’ve never tri…
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 pointers in the C programming language.
The goal of this video is to provide viewers with basic examples to understand and use conditional statements in the C programming language.

828 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