help needed on coversin of an char array to an integer

[MAx]

Hi,
Im kinda stuck in a project at a point where i need an array to
be converted to a
integer using some kind of math.
This board does not support functions like scanf, sscanf etc as
it does not have enough memory to hold their stack.

given a string char str[8] = {'0', '0', '0' , '1' , 'f' , 'b' ,
'c' , 'a' };
i need a function which can convert this array to an integer
( 0x0001fbca )

Expecting a quick response.

Thanks
MAx

[MAx]

On Feb 21, 2:21*pm, MAx <[e-mail]:

Hi,
* * * Im kinda stuck in a project at a point where i need an array to
be converted to a
integer using some kind of math.
* * * This board does not support functions like scanf, sscanf etc as
it does not have enough memory to hold their stack.

* * * given a string *char str[8] = {'0', '0', '0' , '1' , 'f' ,'b' ,
'c' , 'a' };
* * * i need a function which can convert this array to an integer
( 0x0001fbca )

*Expecting a quick response.

Thanks
MAx

I forgot to mention that the contents of the array will be in the
range 0 to 9 and a to f,
its a hex number read inone digit at a time :-)

[Nick Keighley]

On 21 Feb, 09:21, MAx <[e-mail]:

Hi,
* * * Im kinda stuck in a project at a point where i need an array to
be converted to a
integer using some kind of math.
* * * This board does not support functions like scanf, sscanf etc as
it does not have enough memory to hold their stack.

* * * given a string *char str[8] = {'0', '0', '0' , '1' , 'f' ,'b' ,
'c' , 'a' };
* * * i need a function which can convert this array to an integer
( 0x0001fbca )

*Expecting a quick response.

really?

[vippstar]

On Feb 21, 11:21 am, MAx <[e-mail]:

Hi,
Im kinda stuck in a project at a point where i need an array to
be converted to a
integer using some kind of math.
This board does not support functions like scanf, sscanf etc as
it does not have enough memory to hold their stack.

Which "board" is that?

given a string char str[8] = {'0', '0', '0' , '1' , 'f' , 'b' ,
'c' , 'a' };

That is not a string as it is not terminated with a 0.

i need a function which can convert this array to an integer
( 0x0001fbca )

Trivial

Expecting a quick response.

Is it you who expects an answer, or your teacher?

[MisterE]

"MAx" <ma********@gmail.comwrote in message
news:6f**********************************@n77g2000 hse.googlegroups.com...

Hi,
Im kinda stuck in a project at a point where i need an array to
be converted to a
integer using some kind of math.
This board does not support functions like scanf, sscanf etc as
it does not have enough memory to hold their stack.

given a string char str[8] = {'0', '0', '0' , '1' , 'f' , 'b' ,
'c' , 'a' };
i need a function which can convert this array to an integer
( 0x0001fbca )

Expecting a quick response.

Thanks
MAx

int i;
int r = 0;
for (i=0;i<8;i++)
{
if ((str[i] >= '0')&&(str[i]<='9')) r |= str[i] - '0';
else if ((str[i] >= 'A')&&(str[i]<='F')) r |= str[i] - 'A' + 10;
else if ((str[i] >= 'a') && (str[i]<='f')) r |= str[i] - 'a' + 10;
if (i != 7) r <<=4;
}

[vippstar]

On Feb 21, 11:34 am, "MisterE" <[e-mail]:

"MAx" <[e-mail] in message

news:6f**********************************@n77g2000 hse.googlegroups.com...

Hi,
Im kinda stuck in a project at a point where i need an array to
be converted to a
integer using some kind of math.
This board does not support functions like scanf, sscanf etc as
it does not have enough memory to hold their stack.

given a string char str[8] = {'0', '0', '0' , '1' , 'f' , 'b' ,
'c' , 'a' };
i need a function which can convert this array to an integer
( 0x0001fbca )

Expecting a quick response.

Thanks
MAx

int i;
int r = 0;
for (i=0;i<8;i++)
{
if ((str[i] >= '0')&&(str[i]<='9')) r |= str[i] - '0';
else if ((str[i] >= 'A')&&(str[i]<='F')) r |= str[i] - 'A' + 10;
else if ((str[i] >= 'a') && (str[i]<='f')) r |= str[i] - 'a' + 10;
if (i != 7) r <<=4;

}

What makes you think 'A'..'F' (and lowercase) are indeed sequential?
If you plan on posting C code for the OP, then.. at least post code
that works.

Given the restrictions of this, here's a solution I suggest:
--
#include <stdio.h>

int main(void) {

char str[8] = {'0', '0', '0' , '1' , 'f' , 'b' , 'c' , 'a' };
unsigned int i;
FILE * foo;

foo = tmpfile();
if(foo != NULL) {
fwrite(str, 1, sizeof str, foo);
rewind(foo);
fscanf(foo, "%x", &i);
fclose(foo);
}

return 0;
}

[Joachim Schmitz]

vi******@gmail.com wrote:

On Feb 21, 11:34 am, "MisterE" <[e-mail]:

>"MAx" <[e-mail] in message

news:6f**********************************@n77g200 0hse.googlegroups.com...

>>Hi,
Im kinda stuck in a project at a point where i need an array to
be converted to a
integer using some kind of math.
This board does not support functions like scanf, sscanf etc as
it does not have enough memory to hold their stack.

>> given a string char str[8] = {'0', '0', '0' , '1' , 'f' , 'b'
, 'c' , 'a' };
i need a function which can convert this array to an integer
( 0x0001fbca )

>>Expecting a quick response.

>>Thanks
MAx

int i;
int r = 0;
for (i=0;i<8;i++)
{
if ((str[i] >= '0')&&(str[i]<='9')) r |= str[i] - '0';
else if ((str[i] >= 'A')&&(str[i]<='F')) r |= str[i] - 'A' + 10;
else if ((str[i] >= 'a') && (str[i]<='f')) r |= str[i] - 'a' +
10; if (i != 7) r <<=4;

}

What makes you think 'A'..'F' (and lowercase) are indeed sequential?
If you plan on posting C code for the OP, then.. at least post code
that works.

Given the restrictions of this, here's a solution I suggest:

Oops, your "-- " makes the rest a signature and snips your code...
Restored manually:

>#include <stdio.h>

int main(void) {

char str[8] = {'0', '0', '0' , '1' , 'f' , 'b' , 'c' , 'a' };
unsigned int i;
FILE * foo;

foo = tmpfile();
if(foo != NULL) {
fwrite(str, 1, sizeof str, foo);
rewind(foo);
fscanf(foo, "%x", &i);
fclose(foo);
}

return 0;
}

the OP claimed not to be able to use scanf and sscanf as his board doesn't
have this, so what makes you thing he can created files and/or use fscanf?

Bye, Jojo

[Mark Bluemel]

MAx wrote:

Hi,
Im kinda stuck in a project at a point where i need an array to
be converted to a
integer using some kind of math.
This board does not support functions like scanf, sscanf etc as
it does not have enough memory to hold their stack.

given a string char str[8] = {'0', '0', '0' , '1' , 'f' , 'b' ,
'c' , 'a' };
i need a function which can convert this array to an integer
( 0x0001fbca )

Then write one. It's not exactly difficult.

* Start with a running total, set initially to 0.
* Get a digit at a time, convert it into a numeric value,
multiply the running total by 16 and add the digit's value.
* When you run out of digits, you're done

Converting a character (e.g. '9' or 'a') to it's numeric value is a
little more tricky, but not very.

According to the standard, '0' - '9' are contiguous in the character
set, therefore the can always be converted to integers by subtracting
'0', so that's easy.

If you can guarantee that your character set has contiguous alphabetics
(ASCII does, but some representations don't), you can covert alphabetic
characters to their value in the hexadecimal range by subtracting 'a'
(or 'A' as appropriate) and adding 10.

If your character set isn't contiguous (or you're not sure that it will
be so everywhere that your code may need to run), you'll need to use a
lookup table or switch block.

Expecting a quick response.

Nice to see an optimist.

[Old Wolf]

On Feb 21, 10:43 pm, [e-mail] wrote:

>
What makes you think 'A'..'F' (and lowercase) are indeed sequential?

Because they were/are sequential on every single
system that ever had a C compiler?

[Flash Gordon]

Old Wolf wrote, On 22/02/08 12:55:

On Feb 21, 10:43 pm, [e-mail] wrote:

>What makes you think 'A'..'F' (and lowercase) are indeed sequential?

Because they were/are sequential on every single
system that ever had a C compiler?

Are you claiming there were no C compilers for any of the hardware that
uses EBCDIC?
http://groups.google.com/group/comp....a1b727af34b029
--
Flash Gordon

[vippstar]

On Feb 22, 3:47 pm, Flash Gordon <[e-mail]:

Old Wolf wrote, On 22/02/08 12:55:

On Feb 21, 10:43 pm, [e-mail] wrote:

What makes you think 'A'..'F' (and lowercase) are indeed sequential?

Because they were/are sequential on every single
system that ever had a C compiler?

Are you claiming there were no C compilers for any of the hardware that
uses EBCDIC?

In EBCDIC, 'a'..'f' and 'A'..'F' are sequential.
Even if there is no charset, the standard does not guarantee it, and I
believe that's all you need to know.

[Richard Tobin]

In article <ed************@news.flash-gordon.me.uk>,
Flash Gordon <sp**@flash-gordon.me.ukwrote:

>>What makes you think 'A'..'F' (and lowercase) are indeed sequential?

>Because they were/are sequential on every single
system that ever had a C compiler?

>Are you claiming there were no C compilers for any of the hardware that
uses EBCDIC?

The gaps in EBCDIC are between I and J, and R and S.

-- Richard
--
:wq

[Bartc]

"Richard Tobin" <ri*****@cogsci.ed.ac.ukwrote in message
news:fp***********@pc-news.cogsci.ed.ac.uk...

In article <ed************@news.flash-gordon.me.uk>,
Flash Gordon <sp**@flash-gordon.me.ukwrote:

>>>What makes you think 'A'..'F' (and lowercase) are indeed sequential?

>>Because they were/are sequential on every single
system that ever had a C compiler?

>>Are you claiming there were no C compilers for any of the hardware that
uses EBCDIC?

The gaps in EBCDIC are between I and J, and R and S.

Why would whoever put together EBCDIC encoding, put big holes in it like
that?

It would be more understandable if it was accented versions of some
characters, but apparently it's a couple of punctuation characters.

Whoever created it should have been fired.

Even a child would at least have come up with 1 to 26.

--
Bart

[CBFalconer]

Old Wolf wrote:

[e-mail] wrote:

>What makes you think 'A'..'F' (and lowercase) are indeed sequential?

Because they were/are sequential on every single
system that ever had a C compiler?

Oh my. You have led a sheltered life. Read the standard.

--
[mail]: Chuck F (cbfalconer at maineline dot net)
[page]: <http://cbfalconer.home.att.net>
Try the download section.

--
Posted via a free Usenet account from http://www.teranews.com

[CBFalconer]

Ben Bacarisse wrote:

>

.... snip ...

>
BTW, I think there *should* be an 'int toxvalue(int c);' in
standard C since the implementation can do a better job of this
simple conversion than any portable code.

There is:

int hexvalue(int c) {
static const char s = "abcdef";
return (strchr(s, c)) - &s + 10;
}

Convert it into a macro if you wish. It returns 16 for a bad c.

--
[mail]: Chuck F (cbfalconer at maineline dot net)
[page]: <http://cbfalconer.home.att.net>
Try the download section.

--
Posted via a free Usenet account from http://www.teranews.com

[Jean-Marc Bourguet]

"Bartc" <[e-mail]:

"Richard Tobin" <ri*****@cogsci.ed.ac.ukwrote in message

The gaps in EBCDIC are between I and J, and R and S.

Why would whoever put together EBCDIC encoding, put big holes in it like
that?

They were already existing in the code that EBCDIC extended (the E is for
extended).

Whoever created it should have been fired.

Why? They probably did a good job of compromizing between conflicting
constraints you are not aware of.

Yours,

--
Jean-Marc

[CBFalconer]

Bartc wrote:

"Richard Tobin" <ri*****@cogsci.ed.ac.ukwrote:

.... snip ...

>>
The gaps in EBCDIC are between I and J, and R and S.

Why would whoever put together EBCDIC encoding, put big holes in
it like that? It would be more understandable if it was accented
versions of some characters, but apparently it's a couple of
punctuation characters. Whoever created it should have been fired.

Even a child would at least have come up with 1 to 26.

It made the interface with existing punch card systems easy. You
should ask questions, rather than jumping to illogical conclusions.

--
[mail]: Chuck F (cbfalconer at maineline dot net)
[page]: <http://cbfalconer.home.att.net>
Try the download section.

--
Posted via a free Usenet account from http://www.teranews.com

[Richard Tobin]

In article <I0*****************@text.news.virginmedia.com>,
Bartc <[e-mail]:

>Why would whoever put together EBCDIC encoding, put big holes in it like
that?

Because they used punched cards.

>Whoever created it should have been fired.

No-one was ever fired for buying IBM.

Wikipedia quotes a joke:

Professor: So the American government went to IBM to come up with
a data encryption standard, and they came up with-
Student: EBCDIC!

-- Richard
--
:wq

[Richard Tobin]

In article <47***************@yahoo.com>,
CBFalconer <cb********@maineline.netwrote:

>Ben Bacarisse wrote:

>BTW, I think there *should* be an 'int toxvalue(int c);' in
standard C since the implementation can do a better job of this
simple conversion than any portable code.

>There is:

int hexvalue(int c) {
static const char s = "abcdef";
return (strchr(s, c)) - &s + 10;
}

Convert it into a macro if you wish. It returns 16 for a bad c.

Um, strchr() returns NULL if the character is not present, not a
pointer to the terminating '\0'.

Ben's point was that an implementation can typically do a *better* job
than you can in standard C, noth that you can't write it. And I
strongly suspect he intended it to work for all the hex digits, not
just the alphabetic ones.

On the other hand, unless you are concerned to make the non-existent
non-sequential case work, you would probably do reasonably well with

int toxvalue(int c)
{
#if 'B' == 'A'+1 && ... && 'f' == 'a'+5
... obvious ascii-like algorithm ...
#else
... slower general algorithm ...
#endif
}

-- Richard
--
:wq

[Richard Tobin]

In article <47***************@yahoo.com>,
CBFalconer <cb********@maineline.netwrote:

>>What makes you think 'A'..'F' (and lowercase) are indeed sequential?

>Because they were/are sequential on every single
system that ever had a C compiler?

>Oh my. You have led a sheltered life. Read the standard.

I don't have my copy handy. Which system does it mention for which
they are not sequential?

-- Richard
--
:wq

[Flash Gordon]

Ben Bacarisse wrote, On 22/02/08 15:11:

Flash Gordon <sp**@flash-gordon.me.ukwrites:

<snip>

>http://groups.google.com/group/comp....a1b727af34b029

EBCDIC had 'a' to 'f' and 'A' to 'F' sequential, as that post states.

Oops, I must have miss-read it.
--
Flash Gordon

[Flash Gordon]

Richard Tobin wrote, On 22/02/08 15:13:

In article <ed************@news.flash-gordon.me.uk>,
Flash Gordon <sp**@flash-gordon.me.ukwrote:

>>>What makes you think 'A'..'F' (and lowercase) are indeed sequential?

>>Because they were/are sequential on every single
system that ever had a C compiler?

>Are you claiming there were no C compilers for any of the hardware that
uses EBCDIC?

The gaps in EBCDIC are between I and J, and R and S.

OK, the message I spotted giving EBCDIC as a problem was wrong then.
--
Flash Gordon

[Bartc]

"CBFalconer" <cb********@yahoo.comwrote in message
news:47***************@yahoo.com...

Bartc wrote:

>"Richard Tobin" <ri*****@cogsci.ed.ac.ukwrote:

... snip ...

>>>
The gaps in EBCDIC are between I and J, and R and S.

Why would whoever put together EBCDIC encoding, put big holes in
it like that? It would be more understandable if it was accented
versions of some characters, but apparently it's a couple of
punctuation characters. Whoever created it should have been fired.

Even a child would at least have come up with 1 to 26.

It made the interface with existing punch card systems easy. You
should ask questions, rather than jumping to illogical conclusions.

OK I didn't realise there were still mechanical limitations to consider in
the 1960s.

--
Bart

[Joe Wright]

Bartc wrote:

"Richard Tobin" <ri*****@cogsci.ed.ac.ukwrote in message
news:fp***********@pc-news.cogsci.ed.ac.uk...

>In article <ed************@news.flash-gordon.me.uk>,
Flash Gordon <sp**@flash-gordon.me.ukwrote:

>>>>What makes you think 'A'..'F' (and lowercase) are indeed sequential?
Because they were/are sequential on every single
system that ever had a C compiler?
Are you claiming there were no C compilers for any of the hardware that
uses EBCDIC?

The gaps in EBCDIC are between I and J, and R and S.

Why would whoever put together EBCDIC encoding, put big holes in it like
that?

It would be more understandable if it was accented versions of some
characters, but apparently it's a couple of punctuation characters.

Whoever created it should have been fired.

Even a child would at least have come up with 1 to 26.

Why are you kids so much smarter than your forebears?

In the beginning there was the Hollerith Punch Card as presented by IBM
since your grandfather was a boy. The Card was 80 columns wide and 12
rows high. Rows are numbered, top to bottom, 12, 11, 0, 1, 2, 3, 4, 5,
6, 7, 8 and 9. A rectangular 'hole' is 'punched' from the Card to record
alpha-numeric information.

For a given column a numeric digit has a single punch in rows 0 through
9. An alphabetic has two punches per column. For example 'A' is a 12 and
a 1 punch. 'B' is 12 and 2 and so on. 12-9 is 'I'. The next character,
'J', is 11-1, and 'R' will be 11-9.

The next character, 'S' is at 0-2 and finally 'Z' at 0-9.

The Punch Card itself was the data medium for the longest time, until
the advent of magnetic tape. The IBM tape system was 7-channel or six
bits plus parity per character. How shall we translate all this Card
data onto MagTape?

Translate the card column into six bits, 5 and 4 the zone and 3..0 the
field. Translate Card rows 12, 11 and 0 to 11, 10 and 01 such that 0 is
000000 and 9 is 001001. 'A' is 110001, 'J' is 100001 and 'S' is 010010.

This coding system was called BCD or Binary Coded Decimal. It was
limited to 63 characters.

With the advent of the System 360 and 8-bit bytes, IBM extended its
6-bit BCD to 8-bit EBCDIC (Extended Binary Coded Decimal Interchange
Code). EBCDIC includes lower case characters and lots of other
characters in its 255-byte set.

ASCII (American Standard Code for Information Interchange) didn't have
the IBM Punch Card baggage and defined a 7-bit code which survives.

--
Joe Wright
"Everything should be made as simple as possible, but not simpler."
--- Albert Einstein ---

[Randy Howard]

On Fri, 22 Feb 2008 16:45:26 -0600, Bartc wrote
(in article <ag******************@text.news.virginmedia.com> ):

>
"CBFalconer" <cb********@yahoo.comwrote in message
news:47***************@yahoo.com...

>Bartc wrote:

>>"Richard Tobin" <ri*****@cogsci.ed.ac.ukwrote:

... snip ...

>>>>
The gaps in EBCDIC are between I and J, and R and S.

Why would whoever put together EBCDIC encoding, put big holes in
it like that? It would be more understandable if it was accented
versions of some characters, but apparently it's a couple of
punctuation characters. Whoever created it should have been fired.

Even a child would at least have come up with 1 to 26.

It made the interface with existing punch card systems easy. You
should ask questions, rather than jumping to illogical conclusions.

OK I didn't realise there were still mechanical limitations to consider in
the 1960s.

Punch cards were still being used in the early 80s, perhaps later.

--
Randy Howard (2reply remove FOOBAR)
"The power of accurate observation is called cynicism by those
who have not got it." - George Bernard Shaw

[CBFalconer]

Richard Tobin wrote:

CBFalconer <cb********@maineline.netwrote:

>>>What makes you think 'A'..'F' (and lowercase) are indeed
sequential?

>>Because they were/are sequential on every single
system that ever had a C compiler?

>Oh my. You have led a sheltered life. Read the standard.

I don't have my copy handy. Which system does it mention for
which they are not sequential?

Please preserve attributions for any material you quote.

The standard simply does not insist on sequential coding for
non-numeric characters. It never mentions specific systems.

--
[mail]: Chuck F (cbfalconer at maineline dot net)
[page]: <http://cbfalconer.home.att.net>
Try the download section.

--
Posted via a free Usenet account from http://www.teranews.com

[Willem]

Flash wrote:
) Are you claiming there were no C compilers for any of the hardware that
) uses EBCDIC?
) http://groups.google.com/group/comp....a1b727af34b029

On EBCDIC, the characters 'A'..'F' and 'a'..'f' ARE consecutive.

To be more precise: The letters are in sequence, it's just that there
are gaps between i and j, and also between r and s.

SaSW, Willem
--
Disclaimer: I am in no way responsible for any of the statements
made in the above text. For all I know I might be
drugged or something..
No I'm not paranoid. You all think I'm paranoid, don't you !
#EOT

[vippstar]

On Feb 22, 10:52 pm, [e-mail] (Richard Tobin) wrote:

In article <[e-mail]>,

CBFalconer <[e-mail]:

Ben Bacarisse wrote:

BTW, I think there *should* be an 'int toxvalue(int c);' in
standard C since the implementation can do a better job of this
simple conversion than any portable code.

There is:

int hexvalue(int c) {
static const char s = "abcdef";
return (strchr(s, c)) - &s + 10;
}

Convert it into a macro if you wish. It returns 16 for a bad c.

Um, strchr() returns NULL if the character is not present, not a
pointer to the terminating '\0'.

#include <ctype.h>
int tohex(int c) {
static const char s[] = "0123456789abcdef";
return isxdigit((unsigned char)c) ? strchr(s, tolower((unsigned
char)c)) - s : 16;
}
It doesn't make sense for a tohex to return anything other than 0-15,
so the error value here is 16, but it could also be -1.

[CBFalconer]

Willem wrote:

Flash wrote:

>Are you claiming there were no C compilers for any of the
hardware that uses EBCDIC?

.... snip ...

>
On EBCDIC, the characters 'A'..'F' and 'a'..'f' ARE consecutive.

To be more precise: The letters are in sequence, it's just that
there are gaps between i and j, and also between r and s.

I have built char sets that go "aAbBcC...zZ". Very handy for some
sorting problems. What ever gave you the idea that char sets had
to be ASCII or EBCDIC?

--
[mail]: Chuck F (cbfalconer at maineline dot net)
[page]: <http://cbfalconer.home.att.net>
Try the download section.

--
Posted via a free Usenet account from http://www.teranews.com

[Bartc]

"Joe Wright" <jo********@comcast.netwrote in message
news:x8******************************@comcast.com. ..

Bartc wrote:

>"Richard Tobin" <ri*****@cogsci.ed.ac.ukwrote in message
news:fp***********@pc-news.cogsci.ed.ac.uk...

>>The gaps in EBCDIC are between I and J, and R and S.

Why would whoever put together EBCDIC encoding, put big holes in it like
that?

>Even a child would at least have come up with 1 to 26.

....

ASCII (American Standard Code for Information Interchange) didn't have the
IBM Punch Card baggage and defined a 7-bit code which survives.

Thanks, all interesting stuff.

But thinking of it, I remember doing a programming course with punch cards,
on a machine that was definitely not EBCDIC!

So presumably it was just confined to the card reader, immediately converted
to ASCII or SIXBIT, whatever was used.

Only IBM it seems wanted to inflict EBCDIC on all parts of their systems.

--
Bart