K&R Ex 1-3

**Ian Collins** · Jun 27 '08, 07:30 PM

Re: K&R Ex 1-3

Gio wrote:

I'm reading the K&R book and doing the exercises. Currently, I'm working
on Exercise 1-3.
>
Here's what I have:
>

Code:

>
#include <stdio.h>
>
main()

Code:

make that int main(void).

While you are there, turn  your compiler's warnings up, the above should
have caused one.
[QUOTE]
{
    float fahr, celsius;
    float lower, upper, step;
>
    lower = 0;   /* lower limit of temperatuire scale */
    upper = 300; /* upper limit */
    step = 20;   /* step size */
    fahr = lower;
>
    printf("F\t\tC\n");
    while (fahr <= upper) {
        celsius = (5.0/9.0) * (fahr-32.0);
        printf("%4.0f %7.1f\n", fahr, celsius);
        fahr = fahr + step;
    }
}
>
[/QUOTE]

>
Now, this completes the exercise. Technically, anyway. However, I want
to make the "F" and "C" align properly above the right side of their
respective columns.
>

Just add some spaces to the first print and a couple of tabs to the second.

printf(" F\t\t C\n");
printf("%4.0f\t \t%7.1f\n", fahr, celsius);

--
Ian Collins.

**Ben Bacarisse** · Jun 27 '08, 07:30 PM

Re: K&R Ex 1-3

Gio <giomancer@sbcg lobal.netwrites :

I'm reading the K&R book and doing the exercises. Currently, I'm
working on Exercise 1-3.

<snip>

printf("F\t\tC\ n");
while (fahr <= upper) {
celsius = (5.0/9.0) * (fahr-32.0);
printf("%4.0f %7.1f\n", fahr, celsius);
fahr = fahr + step;
}

<snip>

Now, this completes the exercise. Technically, anyway. However, I want
to make the "F" and "C" align properly above the right side of their
respective columns.

I like to do this using the same sizes you have in the numeric
format:

printf("%4s %7s\n", "F", "C");

It keeps everything clear, and you can even wire in a configurable size
from a macro if you really want to (although that is a serious case of
overkill in this exercise).

--
Ben.

**Gio** · Jun 27 '08, 07:30 PM

Re: K&R Ex 1-3

While you are there, turn your compiler's warnings up, the above

should have caused one.

Well.. ah.. I'm working on an Apple II; the compiler I ran this program
on is technically pre-ANSI, but I've kept the differences in mind (and
the documentation close at hand). I figured I could ask a K&R question,
though.

As to why I'm learning C on an Apple IIe.. I'm doing it to get used to
the compiler and the limitations of the computer. And because I'm
slightly nuts. :)

- Gio

--
AND NOW FOR A WORD (an IF blog):

Into the Depths

http://giomancer.wordpress.com/

Roguelike blogspace

**Richard Heathfield** · Jun 27 '08, 07:30 PM

Re: K&R Ex 1-3

Ian Collins said:

Gio wrote:

<snip>

>main()

>
make that int main(void).
>
While you are there, turn your compiler's warnings up, the above should
have caused one.

Why?

--
Richard Heathfield <http://www.cpax.org.uk >
Email: -http://www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999

**Richard Heathfield** · Jun 27 '08, 07:30 PM

Re: K&R Ex 1-3

Gio said:

>While you are there, turn your compiler's warnings up, the above
>should have caused one.

>
Well.. ah.. I'm working on an Apple II; the compiler I ran this program
on is technically pre-ANSI, but I've kept the differences in mind (and
the documentation close at hand). I figured I could ask a K&R question,
though.

You can. K&R C is topical here, although some people here tend to forget
that.

>
As to why I'm learning C on an Apple IIe.. I'm doing it to get used to
the compiler and the limitations of the computer. And because I'm
slightly nuts. :)

....and of course it is *not* comp.lang.c's place to dictate to you what
compiler you must use. Some of the people here occasionally forget that,
too.

(There are, however, definite advantages to be had in bringing yourself
kicking and screaming into the late 1980s. The ANSI C Standard of 1989 was
a significant step forward for C.)

--
Richard Heathfield <http://www.cpax.org.uk >
Email: -http://www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999

**Gio** · Jun 27 '08, 07:30 PM

Re: K&R Ex 1-3

printf("%4s %7s\n", "F", "C");

Aha! This is perfect for me, thank you! I didn't know that it could work
like that. :p

- Gio

--
AND NOW FOR A WORD (an IF blog):

Into the Depths

http://giomancer.wordpress.com/

Roguelike blogspace

**Ian Collins** · Jun 27 '08, 07:30 PM

Re: K&R Ex 1-3

Richard Heathfield wrote:

Ian Collins said:
>

>Gio wrote:

>
<snip>
>

>>main()

>make that int main(void).
>>
>While you are there, turn your compiler's warnings up, the above should
>have caused one.

>
Why?
>

You know why.

--
Ian Collins.

**Richard Heathfield** · Jun 27 '08, 07:30 PM

Re: K&R Ex 1-3

Ian Collins said:

Richard Heathfield wrote:

>Ian Collins said:
>>

>>Gio wrote:

>>
><snip>
>>

>>>main()
>>make that int main(void).
>>>
>>While you are there, turn your compiler's warnings up, the above
>>should have caused one.

>>
>Why?
>>

You know why.

If I knew why, I wouldn't need to ask why. I can see no reason why main()
should require a K&R C implementation (such as the OP is using) to issue a
diagnostic message. Please explain.

--
Richard Heathfield <http://www.cpax.org.uk >
Email: -http://www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999

**Ian Collins** · Jun 27 '08, 07:30 PM

Re: K&R Ex 1-3

Richard Heathfield wrote:

Ian Collins said:
>

>Richard Heathfield wrote:

>>Ian Collins said:
>>>
>>>Gio wrote:
>><snip>
>>>
>>>>main()
>>>make that int main(void).
>>>>
>>>While you are there, turn your compiler's warnings up, the above
>>>should have caused one.
>>Why?
>>>

>You know why.

>
If I knew why, I wouldn't need to ask why. I can see no reason why main()
should require a K&R C implementation (such as the OP is using) to issue a
diagnostic message. Please explain.
>

The OP didn't say he was using such an old compiler until his reply to
my post.

--
Ian Collins.

**Bill Buckels** · Jun 27 '08, 07:30 PM

Re: K&R Ex 1-3

On Apr 19, 8:33 pm, Ian Collins <ian-n...@hotmail.co mwrote:

Richard Heathfield wrote:

Ian Collins said:

>

Gio wrote:

>

<snip>

>

>main()
make that int main(void).

>

While you are there, turn your compiler's warnings up, the above should
have caused one.

>

Why?

>
You know why.
>
--
Ian Collins.

Not on a K&R Compiler. Also warning levels not available on this
particular compiler, however 60% of Apple II developers wrote in Aztec
C. During the mid 80's Aztec C was the largesty selling C compiler.
And the best C compiler of the 80's and perhaps of all time.

Go to the Aztec C Website and take a look:

The Official Aztec C Online Museum

http://www.clipshop.ca/Aztec/index.htm

Bill Bucxels

**Ian Collins** · Jun 27 '08, 07:30 PM

Re: K&R Ex 1-3

Bill Buckels wrote:

On Apr 19, 8:33 pm, Ian Collins <ian-n...@hotmail.co mwrote:

>Richard Heathfield wrote:

>>Ian Collins said:
>>>Gio wrote:
>><snip>
>>>>main()
>>>make that int main(void).
>>>While you are there, turn your compiler's warnings up, the above should
>>>have caused one.
>>Why?

>You know why.
>>

*Please* don't quote signatures.

>
Not on a K&R Compiler.

See my reply to Richard.

--
Ian Collins.

**Richard Heathfield** · Jun 27 '08, 07:30 PM

Re: K&R Ex 1-3

Ian Collins said:

Richard Heathfield wrote:

>Ian Collins said:
>>

>>Richard Heathfield wrote:
>>>Ian Collins said:
>>>>
>>>>Gio wrote:
>>><snip>
>>>>
>>>>>main()
>>>>make that int main(void).
>>>>>
>>>>While you are there, turn your compiler's warnings up, the above
>>>>should have caused one.
>>>Why?
>>>>
>>You know why.

>>
>If I knew why, I wouldn't need to ask why. I can see no reason why
>main() should require a K&R C implementation (such as the OP is using)
>to issue a diagnostic message. Please explain.
>>

The OP didn't say he was using such an old compiler until his reply to
my post.

<shrugThat would be fair enough, if the same point didn't apply to C90
implementations . It would appear from your reply that you assumed, against
the balance of reasonable probability, that he was using a conforming C99
implementation!

Look, if your point is that the int main(void) form is *preferable*, I
agree completely. I use that form myself and recommend it to others. But
there's quite a lot of distance between "this form is preferred to that
form" and "that form should have caused the implementation to issue a
diagnostic message".

Furthermore, K&R C implementations do not, as far as I'm aware, necessarily
support the void keyword (although I accept that it is not reasonable to
expect you to have taken *that* into account in your original reply).

--
Richard Heathfield <http://www.cpax.org.uk >
Email: -http://www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999

**Gio** · Jun 27 '08, 07:30 PM

Re: K&R Ex 1-3

There are, however, definite advantages to be had in bringing

yourself kicking and screaming into the late 1980s. The ANSI C
Standard of 1989 was a significant step forward for C.

*nods* My first experience with coding was a CS class in college; they
taught ANSI C (ISO C was, I think, a year away). The person that makes
the compiler I'm using (Aztec-C) available has been talking to the
company that owns it to see if he can get the source and update it to
ANSI standards.

There is another compiler for the Apple IIe called cc65. It's not too
bad, really, and it is (according to the webpage) almost conforming to
the ISO standard. The program from the K&R book would not compile in it
without modification. Unfortunately, I can't get its output file to run
under ProDOS, which is the OS of choice for the Apple IIe.

While that is probably a personal problem, I'm going down the path of
least resistance for now. :)

- Gio

--
AND NOW FOR A WORD (an IF blog):

Into the Depths

http://giomancer.wordpress.com/

Roguelike blogspace

**Keith Thompson** · Jun 27 '08, 07:30 PM

Re: K&R Ex 1-3

Ian Collins <ian-news@hotmail.co mwrites:

Gio wrote:

>I'm reading the K&R book and doing the exercises. Currently, I'm working
>on Exercise 1-3.
>>
>Here's what I have:
>>
>[code]
>>
>#include <stdio.h>
>>
>main()

>
make that int main(void).
>
While you are there, turn your compiler's warnings up, the above should
have caused one.

[...]

For certain values of "should". A C90-conforming implementation is
not required to issue a diagnostic for that declaration of main,
though a decent one will do so anyway if you ask it nicely.

--
Keith Thompson (The_Other_Keit h) <kst-u@mib.org>
Nokia
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"

K&R Ex 1-3

K&R Ex 1-3

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