How printf() works???????

[sant.tarun@gmail.com]

Hello,

I would appreciate some comments about the piece of code given below
and explanation about the result of this specified code.

int x = 20;

printf("%d %d %d",x < 30, x = 40; x 10);


The output of these code will be :: 0 40 1

Thanks and Regards,
Tarun

[Ulrich Eckhardt]

Re: How printf() works???????

sant.tarun@gmai l.com wrote:

I would appreciate some comments about the piece of code given below
and explanation about the result of this specified code.
>
int x = 20;
>
printf("%d %d %d",x < 30, x = 40; x 10);

It doesn't compile.

The output of these code will be :: 0 40 1

No, see above.

Uli

[Barry Schwarz]

Re: How printf() works???????

On Thu, 6 Mar 2008 21:59:49 -0800 (PST), sant.tarun@gmai l.com wrote:

>
>Hello,
>
>I would appreciate some comments about the piece of code given below
>and explanation about the result of this specified code.
>
>int x = 20;
>
>printf("%d %d %d",x < 30, x = 40; x 10);
>
>
>The output of these code will be :: 0 40 1
>

The code invokes undefined behavior. It modifies x and it evaluates x
more than once and also for a purpose other than determining the new
value. Either condition causes undefined behavior. Therefore,
depending on your frame of mind, any output you receive is correct or
there is no correct output from the program.


Remove del for email

[Richard]

Re: How printf() works???????

Richard Heathfield <rjh@see.sig.in validwrites:

sant.tarun@gmai l.com said:
>

>>
>Hello,
>>
>I would appreciate some comments about the piece of code given below
>and explanation about the result of this specified code.
>>
>int x = 20;
>>
>printf("%d %d %d",x < 30, x = 40; x 10);
>>
>>
>The output of these code will be :: 0 40 1

>
Well, it might be, once you wrap a program around it and fix the syntax
error (a semicolon instead of a comma). First, I'll explain why you might
get that output, and then I'll explain why you might not.
>
x < 30 is a relational expression, and all expressions have values.
Relational expressions have the value 0 if they're false, and 1 if they're
true. So x < 30 will evaluate to 0 if x is less than 30, and 1
otherwise.

It won't actually.

[Robbie Hatley]

Re: How printf() works???????


"Richard" <devr_@gmail.co mwrote:

Richard Heathfield <rjh@see.sig.in validwrites:
>

sant.tarun@gmai l.com said:

>
Hello,
>
I would appreciate some comments about the piece of code given below
and explanation about the result of this specified code.
>
int x = 20;
>
printf("%d %d %d",x < 30, x = 40; x 10);
>
>
The output of these code will be :: 0 40 1

Well, it might be, once you wrap a program around it and fix the syntax
error (a semicolon instead of a comma). First, I'll explain why you might
get that output, and then I'll explain why you might not.

x < 30 is a relational expression, and all expressions have values.
Relational expressions have the value 0 if they're false, and 1 if they're
true. So x < 30 will evaluate to 0 if x is less than 30, and 1
otherwise.

>
It won't actually.

How do you figure? It does in standard C. If it doesn't for you,
then your compiler is broken and you should get a better one.

--
Cheers,
Robbie Hatley
lonewolf aatt well dott com
www dott well dott com slant user slant lonewolf slant

[santosh]

Re: How printf() works???????

Robbie Hatley wrote:

>
"Richard" <devr_@gmail.co mwrote:
>

>Richard Heathfield <rjh@see.sig.in validwrites:
>>

sant.tarun@gmai l.com said:
>
>>
>Hello,
>>
>I would appreciate some comments about the piece of code given
>below and explanation about the result of this specified code.
>>
>int x = 20;
>>
>printf("%d %d %d",x < 30, x = 40; x 10);
>>
>>
>The output of these code will be :: 0 40 1
>
Well, it might be, once you wrap a program around it and fix the
syntax error (a semicolon instead of a comma). First, I'll explain
why you might get that output, and then I'll explain why you might
not.
>
x < 30 is a relational expression, and all expressions have values.
Relational expressions have the value 0 if they're false, and 1 if
they're true. So x < 30 will evaluate to 0 if x is less than 30,
and 1 otherwise.

>>
>It won't actually.

>
How do you figure? It does in standard C. If it doesn't for you,
then your compiler is broken and you should get a better one.

The expression x < 30 will evaluate to 1 if x is less than 30 and zero
otherwise. Richard said the reverse, by mistake I'm sure.

[Robbie Hatley]

Re: How printf() works???????


"santosh" <santosh.k83@gm ail.comwrote:

The expression x < 30 will evaluate to 1 if x is less than 30
and zero otherwise. Richard said the reverse, by mistake I'm sure.

OOOPS!!! So *THAT'S* what you meant! I didn't even notice.
I looked right at what Richard Heathfield wrote several times,
and I didn't see the error. I guess my mind saw what it wanted
to see.

--
Cheers,
Robbie Hatley
lonewolf aatt well dott com
www dott well dott com slant user slant lonewolf slant

[Nick Keighley]

Re: How printf() works???????

On 7 Mar, 09:10, "Robbie Hatley" <lonew...@well. comwrote:

"Richard" <de...@gmail.co mwrote:

Richard Heathfield <r...@see.sig.i nvalidwrites:

>

sant.ta...@gmai l.com said:

>

>Hello,

>

>I would appreciate some comments about the piece of code given below
>and explanation about the result of this specified code.

>

>int x = 20;

>

>printf("%d %d %d",x < 30, x = 40; x 10);

>

>The output of these code will be :: 0 40 1

>

Well, it might be, once you wrap a program around it and fix the syntax
error (a semicolon instead of a comma). First, I'll explain why you might
get that output, and then I'll explain why you might not.

>

x < 30 is a relational expression, and all expressions have values.
Relational expressions have the value 0 if they're false, and 1 if they're
true. So x < 30 will evaluate to 0 if x is less than 30, and 1
otherwise.

>

It won't actually.

>
How do you figure?  It does in standard C.  If it doesn't for you,
then your compiler is broken and you should get a better one.

Richard Heathfield made a typo. He meant "So x < 30 will evaluate to
*1* if x
is less than 30, and *0* otherwise."



--
Nick Keighley

[Kenny McCormack]

Re: How printf() works???????

In article <fqr1fj$68v$1@r egistered.motza rella.org>,
santosh <santosh.k83@gm ail.comwrote:
....

>How do you figure? It does in standard C. If it doesn't for you,
>then your compiler is broken and you should get a better one.

>
>The expression x < 30 will evaluate to 1 if x is less than 30 and zero
>otherwise. Richard said the reverse, by mistake I'm sure.

Yes, it was a mistake.

[santosh]

Re: How printf() works???????

Robbie Hatley wrote:

>
"santosh" <santosh.k83@gm ail.comwrote:
>

>The expression x < 30 will evaluate to 1 if x is less than 30
>and zero otherwise. Richard said the reverse, by mistake I'm sure.

>
OOOPS!!! So *THAT'S* what you meant!

That's what Richard Riley meant when he said "It won't actually."
up-thread.

<snip>

[Richard Heathfield]

Re: How printf() works???????

Robbie Hatley said:

>
"Richard" <devr_@gmail.co mwrote:
>

>Richard Heathfield <rjh@see.sig.in validwrites:
>>

<snip>

>
x < 30 is a relational expression, and all expressions have values.
Relational expressions have the value 0 if they're false, and 1 if
they're true. So x < 30 will evaluate to 0 if x is less than 30, and 1
otherwise.

>>
>It won't actually.

>
How do you figure?

No, he's absolutely right, and it was a good spot. I meant to write: "So x
< 30 will evaluate to 1 if x is less than 30, and 0 otherwise", but
obviously I failed to achieve that objective. If I'd seen his original
correction, I'd have acknowledged it. Since he's in the ol' bozo bin,
however, it escaped my notice until I saw your reply.

And with that one useful article, his signal/noise ratio has just jumped
about a thousand percent. Unfortunately, that isn't particularly difficult
to achieve. But if he spent half, or even quarter, of his articles helping
people instead of carping and sniping, it might even become worth reading
them.

--
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

[Kenny McCormack]

Re: How printf() works???????

In article <hLWdnXOAGZbuj0 zanZ2dnUVZ8s6in Z2d@bt.com>,
Richard Heathfield <rjh@see.sig.in validwrote:
....

>And with that one useful article, his signal/noise ratio has just jumped
>about a thousand percent. Unfortunately, that isn't particularly difficult
>to achieve. But if he spent half, or even quarter, of his articles helping
>people instead of carping and sniping, it might even become worth reading
>them.

Oh. The. Irony...

[Antoninus Twink]

Re: How printf() works???????

On 7 Mar 2008 at 9:21, santosh wrote:

The expression x < 30 will evaluate to 1 if x is less than 30 and zero
otherwise. Richard said the reverse, by mistake I'm sure.

No, I don't think so. Richard HeathField never makes mistakes, as he
often tells us.

[Antoninus Twink]

Re: How printf() works???????

On 7 Mar 2008 at 10:05, Richard Heathfield wrote:

Robbie Hatley said:
>

>>
>"Richard" <devr_@gmail.co mwrote:
>>

>>Richard Heathfield <rjh@see.sig.in validwrites:
>>>

><snip>

>>
>x < 30 is a relational expression, and all expressions have values.
>Relational expressions have the value 0 if they're false, and 1 if
>they're true. So x < 30 will evaluate to 0 if x is less than 30, and 1
>otherwise.
>>>
>>It won't actually.

>>
>How do you figure?

>
No, he's absolutely right, and it was a good spot. I meant to write: "So x
>< 30 will evaluate to 1 if x is less than 30, and 0 otherwise", but
obviously I failed to achieve that objective. If I'd seen his original
correction, I'd have acknowledged it. Since he's in the ol' bozo bin,
however, it escaped my notice until I saw your reply.

Amazing - you can't bring yourself to admit that you screwed up, but
dress it up in this absurd pomposity we've come to expect: "I failed to
achieve the objective of saying something true". FFS.

And with that one useful article, his signal/noise ratio has just
jumped about a thousand percent. Unfortunately, that isn't
particularly difficult to achieve. But if he spent half, or even
quarter, of his articles helping people instead of carping and
sniping, it might even become worth reading them.

Richard Riley has a long history of useful contributions to this group.
Your posting history, on the other hand, reveals a long history of nasty
snipes against Jacob, and complaints about topicality and netiquette. Go
figure.

[Richard]

Re: How printf() works???????

Richard Heathfield <rjh@see.sig.in validwrites:

Robbie Hatley said:
>

>>
>"Richard" <devr_@gmail.co mwrote:
>>

>>Richard Heathfield <rjh@see.sig.in validwrites:
>>>

<snip>

>>
>x < 30 is a relational expression, and all expressions have values.
>Relational expressions have the value 0 if they're false, and 1 if
>they're true. So x < 30 will evaluate to 0 if x is less than 30, and 1
>otherwise.
>>>
>>It won't actually.

>>
>How do you figure?

>
No, he's absolutely right, and it was a good spot. I meant to write: "So x
< 30 will evaluate to 1 if x is less than 30, and 0 otherwise", but
obviously I failed to achieve that objective. If I'd seen his original
correction, I'd have acknowledged it. Since he's in the ol' bozo bin,
however, it escaped my notice until I saw your reply.
>
And with that one useful article, his signal/noise ratio has just jumped
about a thousand percent. Unfortunately, that isn't particularly difficult
to achieve. But if he spent half, or even quarter, of his articles helping
people instead of carping and sniping, it might even become worth reading
them.

This why you see my posts as "carping and sniping". I think you and the
some of the regs make FAR more noise than I. I feel bringing attention
to some of the more outrageous posts here is a little light relief from
the pain of having to read some of the posing that goes on in here.

Robbie's reply is a great example.

Fly into "C God mode" and insult someone.

And yes "your compiler is broken and you should get another one" is
indeed playing the smart alek.

Where are all these "broken C compiler" that regs keep referring to in
here?

How does the world spin without the clc regs keeping it in check?