DATETIME like YYYYMMDDHHMMSS

[Jazzhouse]

Hi,

How do you get the local date time as YYYYMMDDHHMMSS 14 digit string???

I am very new to C++, but if the MSDN tutorials are like that may be it
is better to go with GCC... :)

Ferhat

[White Wolf]

Mike Wahler wrote:
[SNIP]

You can do it the same way in C, C++, VC++, gcc, g++, in fact in any C
or C++ compiler in the world.

#include <time.h>
#include <stdio.h>

time_t t = time(0);
struct tm* lt = localtime(&t);
char time_str[15];
sprintf(time_st r, "%04d%02d%02d%0 2d%02d%02d",
lt->tm_year + 1900, lt->tm_mon + 1, lt->tm_mday,
lt->tm_hour, lt->tm_min, lt->tm_sec);

Untested code

Which part of the above is C++?

All of it. Remember that the C++ standard library contains
the (C90) C standard library. Also, tHe headers with .h, while
deprecated, are indeed part of standard C++.

And it is still a pure C solution. IIRC there was an agreement here that
when showing code, we show C++ code and the best C++ there is to demonstrate
the issue. I see no problem with pure C code as long as it is proven that
that piece of code is the best C++ solution as well.

--
WW aka Attila
:::
Zen meditation isn't what you think...

[John Harrison]

> >

I see no buffer overflow before the year 10000. I don't care about that.
I see. I do, since I do not believe that this is the only way of failure
waiting there.

OK, educate me, where are the other oppotunites for buffer overflow?

I was mainly trying to demonstrate to the OP that the same solution was
possible in C and C++ (he seemed concerned). But if you compare the
partial solution given by Gary Labowitz with mine I would still prefer
the C like solution above. Right tool for the right job I would say.
I have asked if it was a C++ solution. Later (having got the reply I did)

I hinted on it, that it had a buffer overflow opportunity. Prior to that all I have been trying to point out is that it is C and not C++. Reason being
that we have tried for ages here to show C++ solutions or flag the pure C
solutions as such. Or tell (for dumb people like me) why is that C code the best C++ to use.

I did flag it as a C solution. Whether it is the best solution is obviously
a matter of opinion. I just coded what I would have done given the OP's
problem.

john

[Mike Wahler]

"JKop" <NU**@NULL.NULL > wrote in message
news:l6******** ***********@new s.indigo.ie...

Starting with two deprecated headers and followed by pure C code.
which also qualifies as 'pure C++ code'.

int Blah()
{
return 5;
}

int main()
{
Blah(8);
}
Case and point.

What is your point? What you wrote above is *not* valid C++,
but is valid C (99).

C is irrelevant here.
It is relevant to "White Wolf"s remarks, since that was what
he talked about.

Call it what you like. It *is* C++, according to 14882.

Just like a banger is still a car.

I don't know what a 'banger' is. (I'll guess it's some
sort of 'slang', but 'slang' and informal terms imo should
be eschewed in a technical forum. It only leads to confusion.

-Mike

[Mike Wahler]

"White Wolf" <wo***@freemail .hu> wrote in message
news:cj******** **@phys-news1.kolumbus. fi...

Mike Wahler wrote:

All of it apparently.

Starting with two deprecated headers and followed by pure C code.
which also qualifies as 'pure C++ code'.

I see. Do you not want to see the point?

Sure. So tell me what your point is.

Here and
there introducing the opportunity for buffer overruns.
That's a quality issue.

Is it?

Yes. The code is valid C++. Whether it's of 'good quality'
is of course a matter of opinion.
Or is it that code with C++ design is less likely to have that
problem?
What is "C++ design?".

I see. It is code
which compiles with a C++ compiler.

It is code which conforms to the internation standard which
defines the C++ language.

I would not call it C++ code.
The C++ standard does.

Call it what you like. It *is* C++, according to 14882.

It is pure C.

It qualifies as C and C++.
There is nothing C++ to it.
Everything in it is valid C++ according to the C++ standard.
You can call it whatever you
want, that won't change the facts.

That's right. And the facts are that is is valid C++.

-Mike

[Mike Wahler]

"Gary Labowitz" <gl*******@comc ast.net> wrote in message
news:cv******** ************@co mcast.com...

"John Harrison" <jo************ *@hotmail.com> wrote in message
news:2s******** *****@uni-berlin.de...

"White Wolf" <wo***@freemail .hu> wrote in message
news:cj******** **@phys-news1.kolumbus. fi...

Rob Williscroft wrote:
> White Wolf wrote in news:cj******** **@phys-news1.kolumbus. fi in
> comp.lang.c++:
>
>> Which part of the above is C++?
>
> #include <time.h>
> #include <stdio.h>
>
> int main()
> {
> time_t t = time(0);
> struct tm* lt = localtime(&t);
> char time_str[15];
> sprintf(time_st r, "%04d%02d%02d%0 2d%02d%02d",
> lt->tm_year + 1900, lt->tm_mon + 1, lt->tm_mday,
> lt->tm_hour, lt->tm_min, lt->tm_sec
> );
> printf( "%s\n", time_str );
> }
>
> All of it apparently.

Starting with two deprecated headers and followed by pure C code. Here and there introducing the opportunity for buffer overruns. I see. It is code which compiles with a C++ compiler. I would not call it C++ code.
I see no buffer overflow before the year 10000. I don't care about that.

I was mainly trying to demonstrate to the OP that the same solution was
possible in C and C++ (he seemed concerned). But if you compare the

partial

solution given by Gary Labowitz with mine I would still prefer the C like solution above. Right tool for the right job I would say.

I've taught C, and I teach C++. There is not a mention of sprintf and

printf in my C++ courses. Why should there be?
That depends upon your teaching goals. However, for completeness,
perhaps you should at least mention that those functions exist in
C++, even if you don't actually teach about or use them in class.

I don't teach backward compatibility.
Backward compatibility is important in the 'real world'.
I don't even like having to explain
why <ctime> is used instead of just <time>.
I think you meant <time.h>. There is no <time> header in
either language.
Since the languages have diverged, there is no sense to me in trying to keep them together.

Many C++ projects interface with C code. One should be at least
aware of the facilities for dealing with this, even if it's not
part of a "C++ only" course.

$.02,
-Mike

[Mike Wahler]

"White Wolf" <wo***@freemail .hu> wrote in message
news:cj******** **@phys-news1.kolumbus. fi...

Mike Wahler wrote:
[SNIP]

You can do it the same way in C, C++, VC++, gcc, g++, in fact in any C
or C++ compiler in the world.

#include <time.h>
#include <stdio.h>

time_t t = time(0);
struct tm* lt = localtime(&t);
char time_str[15];
sprintf(time_st r, "%04d%02d%02d%0 2d%02d%02d",
lt->tm_year + 1900, lt->tm_mon + 1, lt->tm_mday,
lt->tm_hour, lt->tm_min, lt->tm_sec);

Untested code
Which part of the above is C++?
All of it. Remember that the C++ standard library contains
the (C90) C standard library. Also, tHe headers with .h, while
deprecated, are indeed part of standard C++.

And it is still a pure C solution.

It is a solution which qualifies as legal C *or* C++. Both
language standards support this assertion.
IIRC there was an agreement here that
when showing code, we show C++ code

Well, yes, this is a C++ group.
and the best C++ there is
"Best" will never be agreed upon, since it's a subjective issue.
to demonstrate
the issue.
John gave what he (apparently) felt was the 'best' solution.
What did he feel was 'best' about it? I'm not sure. Perhaps
as simple as that he thought it would be easier for OP to follow
that e.g. something involving containers etc.

I see no problem with pure C code
John's code qualifies according to both standards as C *or* C++.
If it were not valid C, it would not be topical here. So far
I haven't seen anyone challenge the topicality of his code (and
anyone who did would be wrong to do so(.
as long as it is proven that
that piece of code is the best C++ solution as well.

Again, "best" can never be proven. It's a matter of opinion,
and dependent upon context as well.
-Mike

[Mike Wahler]

"White Wolf" <wo***@freemail .hu> wrote in message
news:cj******** **@phys-news1.kolumbus. fi...

Gary Labowitz wrote:

All of it apparently.

Starting with two deprecated headers and followed by pure C code. Here
and there introducing the opportunity for buffer overruns. I see. It
is code which compiles with a C++ compiler. I would not call it C++
code.

Oh, Atilla, you are SO fussy!

Neither. I am Attila and I believe that in a C++ group pure C code should
be flagged as such.

I agree with that, and also add that it should be flagged as
off topic. However John's code does not qualify as such.

-Mike

[Rob Williscroft]

Mike Wahler wrote in news:u7f8d.2569 $M05.241
@newsread3.news .pas.earthlink. net in comp.lang.c++:

I don't even like having to explain
why <ctime> is used instead of just <time>.

I think you meant <time.h>. There is no <time> header in
either language.

That *is* the point, i.e. why is <ctime> not <time>.

Rob.
--
http://www.victim-prime.dsl.pipex.com/

[Mike Wahler]

"Rob Williscroft" <rt*@freenet.co .uk> wrote in message
news:Xn******** *************** ***********@130 .133.1.4...

Mike Wahler wrote in news:u7f8d.2569 $M05.241
@newsread3.news .pas.earthlink. net in comp.lang.c++:

I don't even like having to explain
why <ctime> is used instead of just <time>.

I think you meant <time.h>. There is no <time> header in
either language.

That *is* the point, i.e. why is <ctime> not <time>.

Because as far as I can tell, the 'c' in the name
is to denote that the header comes from the portion
of the C library inherited by the C++ library.

-Mike

[Default User]

White Wolf wrote:

I see. I do, since I do not believe that this is the only way of
failure waiting there.

If you see a problem, point it out. Don't just hint.

Brian Rodenborn