How to print a 32-bit number as a base-10 number

[Steve]

Hi,

Assuming that "division" is a very costly operation (except by any
multiples of 2), whats the fastest way of printing a 32-bit number as a
base-10 unsigned integer.

Thanks
Steve

[Flash Gordon]

On 13 Dec 2004 04:15:11 -0800
"Steve" <st************@yahoo.com> wrote:

Assuming that "division" is a very costly operation (except by any
multiples of 2), whats the fastest way of printing a 32-bit number as
a base-10 unsigned integer.

puts("a 32-bit number as a base-10 unsigned integer.");

The C language does not define the relative speed of different
operations. printf and friends on your implementation might be highly
optimised assembler that you could not beet using C, or it might be
incredibly slow and easy to beet in C. It might be fastest to use
multiply and shift down (I know one processor where this is definitely
true) or multiple might be slow and you are best using a shift and
add/subtract algorithm.

In short, if you want to know what is fast for your implementation you
need to ask in a group dedicated to your platform.
--
Flash Gordon
Living in interesting times.
Although my email address says spam, it is real and I read it.

[Gregory Toomey]

Steve wrote:

Hi,

Assuming that "division" is a very costly operation (except by any
multiples of 2),
Why do you say that? Have you looked at the time complexity of integer
division/multiplication?
whats the fastest way of printing a 32-bit number as a
base-10 unsigned integer.

Thanks
Steve

printf("%d",number);

gtoomey

[dandelion]

"Gregory Toomey" <no****@bigpond.com> wrote in message
news:32*************@individual.net...

Steve wrote:

Hi,

Assuming that "division" is a very costly operation (except by any
multiples of 2),

Why do you say that?

It was in his assignment.

[Walter]

"Steve" <st************@yahoo.com> wrote in message
news:11**********************@z14g2000cwz.googlegr oups.com...

Assuming that "division" is a very costly operation (except by any
multiples of 2), whats the fastest way of printing a 32-bit number as a
base-10 unsigned integer.

Printing a number goes through the I/O system, which is commonly orders of
magnitude slower than a few divides. You'll likely never notice the overhead
of the divides when printing numbers.

Assumptions about where a program is spending its time are usually wrong,
even when assumed by experts. A profiler will give you accurate information
that is often surprising.

Digital Mars C is a free download and comes with a profiler
www.digitalmars.com/ctg/trace.html.

-Walter
www.digitalmars.com free C, C++, D compilers

[Martin Ambuhl]

Steve wrote:

Hi,

Assuming that "division" is a very costly operation (except by any
multiples of 2), whats the fastest way of printing a 32-bit number as a
base-10 unsigned integer.

The fastest way (in terms of execution) is completely
implement-dependent. The fastest way to write it is with printf:

#include <stdio.h>

int main(void)
{
unsigned long x = 42; /* note that the guaranteed range of 'int'
is not sufficient. */
printf("%lu\n", x);
return 0;
}