«

How to write a C programming that it may output the char one after
one every other second?

For example: char a[50]="hello world!" output h,next second output
e,next second output l...

liking C lang. wrote:
> How to write a C programming that it may output the char one after
> one every other second?
>
> For example: char a[50]="hello world!" output h,next second output
> e,next second output l...

I'm going to assume you know how to write a loop to print the string
one character at a time. If you do, the only thing you need to add is
code to wait a second on each iteration. Take a look at the functions
in <time.h>. In particular, take a look at the standard library
function clock. In pseudo-code, you could write

now = clock();
while (clock() - now < 1 second)
{ /* do nothing */ }

You should be able to adjust this to make it valid C.

"=?utf-8?B?SGFyYWxkIHZhbiBExLNr?=" <> wrote:

> liking C lang. wrote:
> > How to write a C programming that it may output the char one after
> > one every other second?
>
> I'm going to assume you know how to write a loop to print the string
> one character at a time. If you do, the only thing you need to add is
> code to wait a second on each iteration. Take a look at the functions
> in <time.h>. In particular, take a look at the standard library
> function clock. In pseudo-code, you could write
>
> now = clock();
> while (clock() - now < 1 second)
> { /* do nothing */ }
>
> You should be able to adjust this to make it valid C.

You could, but you'd be wrong. clock() measures processor time used, not
real time. For that, you want time() and difftime().

But even then, in the general case you're better off not using this
busy-loop method of waiting. On a multi-threaded system, it will have a
negative impact on the performance of your computer, and on a multi-user
system, it's extremely anti-social. What you want to do is (as usual)
read the FAQ: <http://c-faq.com/osdep/subsecond.html>

Richard

Richard Bos wrote:
> "=?utf-8?B?SGFyYWxkIHZhbiBExLNr?=" <> wrote:
>
> > liking C lang. wrote:
> > > How to write a C programming that it may output the char one after
> > > one every other second?
> >
> > I'm going to assume you know how to write a loop to print the string
> > one character at a time. If you do, the only thing you need to add is
> > code to wait a second on each iteration. Take a look at the functions
> > in <time.h>. In particular, take a look at the standard library
> > function clock. In pseudo-code, you could write
> >
> > now = clock();
> > while (clock() - now < 1 second)
> > { /* do nothing */ }
> >
> > You should be able to adjust this to make it valid C.
>
> You could, but you'd be wrong. clock() measures processor time used, not
> real time. For that, you want time() and difftime().

Ah, right, thank you for that.

> But even then, in the general case you're better off not using this
> busy-loop method of waiting. On a multi-threaded system, it will have a
> negative impact on the performance of your computer, and on a multi-user
> system, it's extremely anti-social. What you want to do is (as usual)
> read the FAQ: <http://c-faq.com/osdep/subsecond.html>

As the FAQ mentions, there is no way in standard C for sub-second
resolution. However, the OP wanted to wait exactly one second. That is
possible in standard C (to the best of the computer's ability). It's
unfortunate that the only standard way of doing this is anti-social on
multi-user systems, but if the OP is interested in learning C, in this
case it may be a better solution than other alternatives, and there
may be no other users to worry about yet.

On 2ÔÂ16ÈÕ, ÏÂÎç5ʱ22·Ö, r...@hoekstra-uitgeverij.nl (Richard Bos) wrote:
> "=?utf-8?B?SGFyYWxkIHZhbiBExLNr?=" <true...@gmail.com> wrote:
> > liking C lang. wrote:
> > > How to write a C programming that it may output the char one after
> > > one every other second?
>
> > I'm going to assume you know how to write a loop to print the string
> > one character at a time. If you do, the only thing you need to add is
> > code to wait a second on each iteration. Take a look at the functions
> > in <time.h>. In particular, take a look at the standard library
> > function clock. In pseudo-code, you could write
>
> > now = clock();
> > while (clock() - now < 1 second)
> > { /* do nothing */ }
>
> > You should be able to adjust this to make it valid C.
>
> You could, but you'd be wrong. clock() measures processor time used, not
> real time. For that, you want time() and difftime().
>
> But even then, in the general case you're better off not using this
> busy-loop method of waiting. On a multi-threaded system, it will have a
> negative impact on the performance of your computer, and on a multi-user
> system, it's extremely anti-social. What you want to do is (as usual)
> read the FAQ: <http://c-faq.com/osdep/subsecond.html>
>
> Richard- Òþ²Ø±»ÒýÓÃÎÄ×Ö -
>
> - ÏÔʾÒýÓõÄÎÄ×Ö -


as the FAQ mentions,use a do-nothing loop like
for(i=0;i<10000000;i++)
;
Ah,my computer must be too tired to crash.But this method is also a
better way.
Thank you.

Harald van Dijk wrote:
> Richard Bos wrote:
> > "=?utf-8?B?SGFyYWxkIHZhbiBExLNr?=" <> wrote:
> >
> > > liking C lang. wrote:
> > > > How to write a C programming that it may output the char one after
> > > > one every other second?
> > >
> > > I'm going to assume you know how to write a loop to print the string
> > > one character at a time. If you do, the only thing you need to add is
> > > code to wait a second on each iteration. Take a look at the functions
> > > in <time.h>. In particular, take a look at the standard library
> > > function clock. In pseudo-code, you could write
> > >
> > > now = clock();
> > > while (clock() - now < 1 second)
> > > { /* do nothing */ }
> > >
> > > You should be able to adjust this to make it valid C.
> >
> > You could, but you'd be wrong. clock() measures processor time used, not
> > real time. For that, you want time() and difftime().
>
> Ah, right, thank you for that.
>
> > But even then, in the general case you're better off not using this
> > busy-loop method of waiting. On a multi-threaded system, it will have a
> > negative impact on the performance of your computer, and on a multi-user
> > system, it's extremely anti-social. What you want to do is (as usual)
> > read the FAQ: <http://c-faq.com/osdep/subsecond.html>
>
> As the FAQ mentions, there is no way in standard C for sub-second
> resolution. However, the OP wanted to wait exactly one second. That is
> possible in standard C (to the best of the computer's ability). It's
> unfortunate that the only standard way of doing this is anti-social on
> multi-user systems, but if the OP is interested in learning C, in this
> case it may be a better solution than other alternatives, and there
> may be no other users to worry about yet.

I don't think it's possible, in the sense that it is guaranteed,
within standard C, to pause any length of time. You can get the
current time with time(), but in a multitasking system, the OS might
decide to preempt your program such that, you overshoot the
requirements. clock(), of course, measures processor time, which is
different. Realtime behaviour is not guaranteed under preemptively
multitasking systems. The best you can get is to elevate your priority
and set a alarm or timer. All that is of course beyond the scope of
this group.

liking C lang. wrote:
> On 2ÔÂ16ÈÕ, ÏÂÎç5ʱ22·Ö, r...@hoekstra-uitgeverij..nl (Richard Bos) wrote:
> > "=?utf-8?B?SGFyYWxkIHZhbiBExLNr?=" <true...@gmail.com> wrote:
> > > liking C lang. wrote:
> > > > How to write a C programming that it may output the char one after
> > > > one every other second?
> >
> > > I'm going to assume you know how to write a loop to print the string
> > > one character at a time. If you do, the only thing you need to add is
> > > code to wait a second on each iteration. Take a look at the functions
> > > in <time.h>. In particular, take a look at the standard library
> > > function clock. In pseudo-code, you could write
> >
> > > now = clock();
> > > while (clock() - now < 1 second)
> > > { /* do nothing */ }
> >
> > > You should be able to adjust this to make it valid C.
> >
> > You could, but you'd be wrong. clock() measures processor time used, not
> > real time. For that, you want time() and difftime().
> >
> > But even then, in the general case you're better off not using this
> > busy-loop method of waiting. On a multi-threaded system, it will have a
> > negative impact on the performance of your computer, and on a multi-user
> > system, it's extremely anti-social. What you want to do is (as usual)
> > read the FAQ: <http://c-faq.com/osdep/subsecond.html>
> >
> > Richard- Òþ²Ø±»ÒýÓÃÎÄ×Ö -
>
> as the FAQ mentions,use a do-nothing loop like
> for(i=0;i<10000000;i++)
> ;
> Ah,my computer must be too tired to crash.But this method is also a
> better way.

No it isn't. It's system and load specific. If you really want to do
this in a robust manner, you'll have to look at whatever facilities
that are offered by your system. For a toy or demo program, the above
method or what Harald suggested are probably fine.

"liking C lang." <> wrote:

> On 2=D4=C216=C8=D5, =CF=C2=CE=E75=CA=B122=B7=D6, r...@hoekstra-uitgeverij.n=
> l (Richard Bos) wrote:
> > But even then, in the general case you're better off not using this
> > busy-loop method of waiting. On a multi-threaded system, it will have a
> > negative impact on the performance of your computer, and on a multi-user
> > system, it's extremely anti-social. What you want to do is (as usual)
> > read the FAQ: <http://c-faq.com/osdep/subsecond.html>
> >
> > Richard- =D2=FE=B2=D8=B1=BB=D2=FD=D3=C3=CE=C4=D7=D6 -
> >
> > - =CF=D4=CA=BE=D2=FD=D3=C3=B5=C4=CE=C4=D7=D6 -

No, I didn't post all that quoted-illegible crap. Don't do that.

> as the FAQ mentions,use a do-nothing loop like

Obviously you haven't read that page for comprehension. The FAQ
specifically and strongly says _not_ to use a do-nothing loop like that.

> for(i=3D0;i<10000000;i++)
> ;

> Ah,my computer must be too tired to crash.But this method is also a
> better way.

No, it is massively inferior to using your brain and a system-specific
method. It is even greatly inferior to using time(). About the only
thing it is not inferior to is asking the user to use a stopwatch and
press enter every second.

Richard

"liking C lang." <> schrieb im Newsbeitrag
news: oups.com...
> How to write a C programming that it may output the char one after
> one every other second?
>
> For example: char a[50]="hello world!" output h,next second output
> e,next second output l...
in POSIX there is sleep(int seconds); maybe that helps here

bye, Jojo

On 2ÔÂ16ÈÕ, ÏÂÎç9ʱ49·Ö, "Joachim Schmitz" <nospam.schm...@hp.com> wrote:
> "liking C lang." <2008mu...@gmail.com> schrieb im Newsbeitragnews:1171614832.759778.132930@a75g2000c wd.googlegroups.com...> How to write a C programming that it may output the char one after
> > one every other second?
>
> > For example: char a[50]="hello world!" output h,next second output
> > e,next second output l...
>
> in POSIX there is sleep(int seconds); maybe that helps here
>
> bye, Jojo

I think this method is best answer for the OP.
Thank you, Jojo.