Complex numbers and printf

[jacob navia]

The C99 standard forgot to define the printf equivalent for complex numbers
Since I am revising the lcc-win implementation of complex numbers
I decided to fill this hole with
"Z"

for instance
double _Complex m = 2+3*I;
printf("%Zg\n", m);
will print
2+3*I

The alternative flag makes this look like:

printf("%#Zg\n" ,m);
2.00000+3.00000 i

--
jacob navia
jacob at jacob point remcomp point fr
logiciels/informatique
http://www.cs.virginia.edu/~lcc-win32

[Eric Sosman]

Morris Dovey wrote:

Bartc wrote:

>But inventing new printf formats is fun; how about the following for
printing arrays and blocks of data:

int a[] = {10,20,30,40,50 ,60};

printf(" (%A,%d)\n",a,6) ;

will print: (10,20,30,40,50 ,60)

%A means array print, the parameter should point to the data. An extra
int/size_t parameter is how many values to print. The format of each element
follows (%d). The text between %A and %d is separator chars. Maybe %10A for
10 elems per line.

Might get more use than %Z anyway.

Cool! How about:

printf("%f",a[i=0; i<6; i++]);

Ahhh, that conjures up memories, that does. It was hard
work shovelling punched cards into the computer's firebox
(steam-powered computers in those days; had to keep up the
pressure if you wanted any accuracy), but back then I was
young, and strong, and stupid in that particular way that
expressed itself in ever more ingenious combinations of WRITE
and FORMAT. Little programming languages embedded inside the
larger one, seeming at times almost Turing-complete.

The old memories fade and blur, but never quite die ...

--
Er*********@sun .com

[Morris Dovey]

bu************* ****@AM.gmail.c om wrote:

>
Morris Dovey <mr*****@iedu.c omwrites:

printf("%f ",a[i=0; i<6; i++]);

Heh, I just had to try that thinking I missed a new feature of C99 ;-)

I wish. It was just an "implied DO loop" adapted from FORTRAN IV
(and later) READ/WRITE statements - wishful thinking on my part.

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/Stirling/

[burton.samogradHEY]

Morris Dovey <mr*****@iedu.c omwrites:

bu************* ****@AM.gmail.c om wrote:

>>
Morris Dovey <mr*****@iedu.c omwrites:

printf("%f ",a[i=0; i<6; i++]);

Heh, I just had to try that thinking I missed a new feature of C99 ;-)

I wish. It was just an "implied DO loop" adapted from FORTRAN IV
(and later) READ/WRITE statements - wishful thinking on my part.

Wow, that's an interesting syntactic construct for a complied
language. I haven't looked at FORTRAN at all, but that's pretty
interesting that they have that feature. I was looking closer at the
C version you wrote and was wondering if it even could be implemented
in your typical C compiler...

/me goes off to read more about FORTRAN...

--
burton

[Walter Roberson]

In article <fq**********@a ioe.org>, jacob navia <ja***@nospam.o rgwrote:

>Walter Roberson wrote:

>Because it gives an opportunity to demonstrate the incomparible
beauty of operator overloading??

>Operator overloading in printf?

Why -not- operator overloading in printf() ? Other than, of course,
the matter of whether printf() qualifies as an "operator"
or not.

Urrr, you do allow operator overloading of varadic functions,
don't you?

>Funny how much nonsense you can say. Are you paid by the nonsense line?
Or you do it for free as a hobby?

Why, the union contract sets out a monthly quota of course.

--
"Prevention is the daughter of intelligence."
-- Sir Walter Raleigh

[Serve Laurijssen]

"Walter Roberson" <ro******@ibd.n rc-cnrc.gc.caschre ef in bericht
news:fq******** **@canopus.cc.u manitoba.ca...

In article <87************ @kvetch.smov.or g>,
Keith Thompson <ks***@mib.orgw rote:

>>Second, it's inflexible; it imposes one of two output representations
for complex numbers. If I want to print "2+3*I", I can write:

> printf("%g+%g*I \n", creal(m), cimag(m));

>>If I want to print "2 + 3i", of course, I can write:

> printf("%g + %gi\n", creal(m), cimag(m));

>>which your extension doesn't support, but the standard already does.

Then there is engineering, in which the imaginary constant is
usually represented as 'j' instead of 'i' or 'I'.

I guess that is why it isnt put in and it wasnt an oversight.
It is interesting to see that in C++ you can output complex numbers with
cout, although I dont know if thats standard.

std::complex<do ublec(5., 6.);
std::cout << c << std::endl;

this prints: "(5,6)" on my machine

If thats standard I would say use that same mechanism in lccwin32 too and
also in the C standard if it ever gets adopted. More consistent this way

--
"Style is instinctive and few achieve it in a notable degree. Its
development is not hastened by instruction. It comes or it doesn't.
It will take care of itself." -- Walter J. Phillips

[Noob]

"We're sorry. You have reached an imaginary number. Please rotate
your phone 90 degrees and try again."