Same program in C and in C#. C# is faster than C. How Come ?

[c]

Hi every one,

Me and my Cousin were talking about C and C#, I love C and he loves
C#..and were talking C is ...blah blah...C# is Blah Blah ...etc

and then we decided to write a program that will calculate the
factorial of 10, 10 millions time and print the reusult in a file with
the name log.txt..

I wrote something like this

#include <stdio.h>
unsigned int fib (int n);

int main()
{
FILE *fp;
unsigned int loop =1 ;
if ( (fp = fopen( "log.txt", "a" )) != NULL )
for (loop; loop <= 10000000 ; loop++)
{

fprintf(fp,"%u\ n",fib(10));
}
fclose (fp);
return 0;
}

unsigned int fib (int n)
{ if (n != 1 )
return n * fib(n-1);
else
return 1;
}
and he did the something in C#
and then we all have the same laptop..DELL Inspiron 6000.

I ran my program, I took 18 seconds to get done..his program took 7
seconds..Wow

and then I asked him to run my program in his laptop..it's all the
same ..but I wanted to...I ran it...gave me the same time..

How come ..?!

Next day, I tried some Optimization

and developed the loop and wrote something like this

for (loop; loop <= 1000000 ; loop++)
{
fprintf(fp,"%u\ n %u\n %u\n %u\n %u\n
",fib(10),fib(1 0),fib(10),fib( 10),fib(10));
fprintf(fp,"%u\ n %u\n %u\n %u\n %u\n
",fib(10),fib(1 0),fib(10),fib( 10),fib(10));
}

But his program still faster than mine..

then, I tried the program under Slackware 12....it took 3.8 Seconds to
get done..Wow, I won the Challenge..

anyway, he want me to beat him under windows XP...Please guys help me
out..

[Default User]

c wrote:

On Dec 13, 2:51 am, Francine.Ne...@ googlemail.com wrote:

The answer to your question is 42.

What do you mean by 42..please give me more details..

<http://en.wikipedia.org/wiki/Answer_...se%2C_and_Ever
ything>

Brian

[pete]

c wrote:

>
On Dec 13, 3:07 am, pete <pfil...@mindsp ring.comwrote:

My first guess is that fprintf is your slowest dog.
The second most obvious improvement would be to
remove recursion from your fib function.

Your program runs in 19 cursor blinks on my machine.
My program, new.c, runs in 11 cursor blinks.

thanks pete...
But I gotta use recursion..It's not fair..My friend uses recursion in
his program, the program that he wrote in C#..So I have to :-)
otherwise, I am cheating.

I put the recursion back in and timed it again.
It's still just as fast.
Why didn't you try that first yourself?

/* BEGIN new.c */

#include <stdio.h>
#include <limits.h>

long unsigned fib(int n);
void lutoa(long unsigned n, char *s);

int main(void)
{
FILE *fp;
long unsigned loop = 10000000;
char lutoa_buff[(sizeof(long) * CHAR_BIT ) / 3 + 1];

if ((fp = fopen("log.txt" , "w")) != NULL) {
do {
lutoa(fib(10), lutoa_buff);
fputs(lutoa_buf f, fp);
putc('\n', fp);
} while (--loop != 0);
fclose (fp);
}
return 0;
}

long unsigned fib(int n)
{
return n != 1 ? n * fib(n - 1) : 1;
}

void lutoa(long unsigned n, char *s)
{
long unsigned tenth;
char *p, swap;

p = s;
tenth = n;
do {
tenth /= 10;
*p++ = (char)(n - 10 * tenth + '0');
n = tenth;
} while (tenth != 0);
*p-- = '\0';
while (p s) {
swap = *s;
*s++ = *p;
*p-- = swap;
}
}

/* END new.c */
--
pete

[c]

On Dec 13, 3:43 am, pete <pfil...@mindsp ring.comwrote:

c wrote:

On Dec 13, 3:07 am, pete <pfil...@mindsp ring.comwrote:

My first guess is that fprintf is your slowest dog.
The second most obvious improvement would be to
remove recursion from your fib function.

Your program runs in 19 cursor blinks on my machine.
My program, new.c, runs in 11 cursor blinks.

thanks pete...
But I gotta use recursion..It's not fair..My friend uses recursion in
his program, the program that he wrote in C#..So I have to :-)
otherwise, I am cheating.

I put the recursion back in and timed it again.
It's still just as fast.
Why didn't you try that first yourself?

/* BEGIN new.c */

#include <stdio.h>
#include <limits.h>

long unsigned fib(int n);
void lutoa(long unsigned n, char *s);

int main(void)
{
FILE *fp;
long unsigned loop = 10000000;
char lutoa_buff[(sizeof(long) * CHAR_BIT ) / 3 + 1];

if ((fp = fopen("log.txt" , "w")) != NULL) {
do {
lutoa(fib(10), lutoa_buff);
fputs(lutoa_buf f, fp);
putc('\n', fp);
} while (--loop != 0);
fclose (fp);
}
return 0;

}

long unsigned fib(int n)
{
return n != 1 ? n * fib(n - 1) : 1;

}

void lutoa(long unsigned n, char *s)
{
long unsigned tenth;
char *p, swap;

p = s;
tenth = n;
do {
tenth /= 10;
*p++ = (char)(n - 10 * tenth + '0');
n = tenth;
} while (tenth != 0);
*p-- = '\0';
while (p s) {
swap = *s;
*s++ = *p;
*p-- = swap;
}

}

/* END new.c */

--
pete

Thank you very much, that's very sweet of you.

[c]

On Dec 13, 3:46 am, "Default User" <defaultuse...@ yahoo.comwrote:

c wrote:

On Dec 13, 2:51 am, Francine.Ne...@ googlemail.com wrote:

The answer to your question is 42.

What do you mean by 42..please give me more details..

<http://en.wikipedia.org/wiki/Answer_...se%2C_and_Ever
ything>

Brian

still don't know that do you guys mean by 42!!
!
!!
!!!

[Tor Rustad]

c wrote:

Hi every one,

Me and my Cousin were talking about C and C#, I love C and he loves
C#..and were talking C is ...blah blah...C# is Blah Blah ...etc

and then we decided to write a program that will calculate the
factorial of 10, 10 millions time and print the reusult in a file with
the name log.txt.

Methinks, you are not really measuring program speed, but I/O performance.

You was printing '3628800' 10 million times, that's only 7 bytes per I/O.

In C, try using fwrite() instead, and issue only one I/O per 4 kb, even
better should be one I/O per 64 kb. If doing that, I guess you drop
below 2 seconds on XP.

--
Tor <bw****@wvtqvm. vw | tr i-za-h a-z>

[Doug]

On Dec 13, 12:27 am, c <alcon...@gmail .comwrote:

c wrote:

Hi every one,

Me and my Cousin were talking about C and C#, I love C and he loves
C#..and were talking C is ...blah blah...C# is Blah Blah ...etc

<snip>

My friend uses recursion in

his program, the program that he wrote in C#..So I have to :-)
otherwise, I am cheating.

Hi c,

At the risk of starting yet another flame war on topicality... This
is all OT here, and you'd be better asking...mmm, I'm really not sure
actually. A windows comp group, maybe.

Have you checked the compiler settings you used when you compiled on
XP? (Richard Tobin mentioned this above, not sure if you spotted it.)

The fib() function you list (which, as others have said, should
probably be called fact()!) is an excellent candidate for
optimisation. Google for "tail recursion". If you turn up the
optimisation on your compiler then this might kick in and help a bit.

But I think that might be cheating too. AFAIK, the current C#
compiler doesn't use this optimisation. (The CLR supports it, but the
C# compiler doesn't yet emit it.) So I don't think your cousin's
program benefits from this. (Don't take my word as gospel.)

But as others have stated, it actually looks like it's the IO that's
being compared at the moment. I guess you're really comparing your c
standard lib implementation against the CLR, in one particular use
case.

Which is interesting, but probably not what you and your cousin set
out to compare. Maybe you and your cousin could come up with a range
of other tests - like purely compute-bound (crunch some matrices or
calculate some primes) or IO-bound (copy some files).

Doug

[Ian Collins]

c wrote:

Hi every one,

Me and my Cousin were talking about C and C#, I love C and he loves
C#..and were talking C is ...blah blah...C# is Blah Blah ...etc

and then we all have the same laptop..DELL Inspiron 6000.

I ran my program, I took 18 seconds to get done..his program took 7
seconds..Wow

Must be down to your compiler or options, your code ran in 3 seconds on
my laptop (Dell M60, same CPU as the Inspiron 6000) and 1 second on my
desktop...

--
Ian Collins.

[Gene]

On Dec 12, 6:23 pm, c <alcon...@gmail .comwrote:

Hi every one,

Me and my Cousin were talking about C and C#, I love C and he loves
C#..and were talking C is ...blah blah...C# is Blah Blah ...etc

and then we decided to write a program that will calculate the
factorial of 10, 10 millions time and print the reusult in a file with
the name log.txt..

[ code elided ]

The two compilers you mentioned don't do much code optimization. On
the other hand, the MS C# compiler has a huge investment in the latest
technologies. If you use, say, Visual C++ 2005 Express Edition (which
I mention only because it's freely downloadable) and highest
optimization settings, the difference ought to be much smaller. Which
will be faster will depend on unpredictable details. For example,
some very aggressive optimizers will inline-expand a recursive
function in nested fashion a few times a la loop unrolling. This can
lead to very big speedups for codes like yours. Don't know if C# does
that. I don't think VC++ EE does.

[user923005]

On Dec 12, 4:05 pm, c <alcon...@gmail .comwrote:

On Dec 13, 2:54 am, user923005 <dcor...@connx. comwrote:

On Dec 12, 3:23 pm, c <alcon...@gmail .comwrote:

Hi every one,

Me and my Cousin were talking about C and C#, I love C and he loves
C#..and were talking C is ...blah blah...C# is Blah Blah ...etc

and then we decided to write a program that will calculate the
factorial of 10, 10 millions time and print the reusult in a file with
the name log.txt..

I wrote something like this

#include <stdio.h>
unsigned int fib (int n);

int main()
{
FILE *fp;
unsigned int loop =1 ;
if ( (fp = fopen( "log.txt", "a" )) != NULL )
for (loop; loop <= 10000000 ; loop++)
{

fprintf(fp,"%u\ n",fib(10));
}
fclose (fp);
return 0;

}

unsigned int fib (int n)
{ if (n != 1 )
return n * fib(n-1);
else
return 1;
}

and he did the something in C#

and then we all have the same laptop..DELL Inspiron 6000.

I ran my program, I took 18 seconds to get done..his program took 7
seconds..Wow

and then I asked him to run my program in his laptop..it's all the
same ..but I wanted to...I ran it...gave me the same time..

How come ..?!

Next day, I tried some Optimization

and developed the loop and wrote something like this

for (loop; loop <= 1000000 ; loop++)
{
fprintf(fp,"%u\ n %u\n %u\n %u\n %u\n
",fib(10),fib(1 0),fib(10),fib( 10),fib(10));
fprintf(fp,"%u\ n %u\n %u\n %u\n %u\n
",fib(10),fib(1 0),fib(10),fib( 10),fib(10));
}

But his program still faster than mine..

then, I tried the program under Slackware 12....it took 3.8 Seconds to
get done..Wow, I won the Challenge..

anyway, he want me to beat him under windows XP...Please guys help me
out..

The recursive factorial function will be a lot slower than an
iterative one.
But the lion's share of the time is going to be in writing out the
text file.
It occupies 160 MB on my machine. It appears that your friend has a
faster disk than you do.
This might be marginally faster:

#include <stdio.h>

unsigned fact(unsigned n)
{
unsigned result = 1;
while (n-- 1)
result *= n;
return result;

}

int main()
{
FILE *fp;
unsigned loop;
if ((fp = fopen("log.txt" , "a")) != NULL) {
setvbuf(fp, NULL, _IOFBF, 16000);
for (loop=1; loop <= 10000000; loop++) {
fprintf(fp, "%u\n", fact(10));
}
fclose(fp);
}
return 0;

}

This program executes in less than one second on my machine (showing
that the time is almost exclusively I/O):

#include <stdio.h>

unsigned fact(unsigned n)
{
unsigned result = 1;
while (n-- 1)
result *= n;
return result;

}

int main()
{
FILE *fp;
unsigned loop;
double sum = 0;
if ((fp = fopen("log.txt" , "a")) != NULL) {
setvbuf(fp, NULL, _IOFBF, 16000);
for (loop=1; loop <= 10000000; loop++) {
sum += fact(10);
}
printf("sum was %f\n", sum);
fclose(fp);
}
return 0;}

/*
C:\tmp>foo
sum was 3628800000000.0 00000
*/

Thanks sir for you reply..
you mentioned "It appears that your friend has a
faster disk than you do"
We both have the same laptop..same model..anyway, I tested my program
in his laptop just in case..
anyway, I compiled the code you posted..its save a 0-byte text file on
machine..
I will try with another compiler..I'll get back to you..

If your disk drives are the same, that indicates that the buffered I/O
of C# is superior to the buffered I/O of C.

You must have compiled the second program, which does not write
anything to disk.
The first program writes a 160 MB file.

Here is a very cheesy alternative:

#include <stdio.h>
#include <string.h>
#include <errno.h>

unsigned fact(unsigned n)
{
unsigned result = 1;
while (n-- 1)
result *= n;
return result;
}

static char absurd_buffer[160000000];

int main(void)
{
FILE *fp;
unsigned loop;
if ((fp = fopen("log.txt" , "w")) != NULL) {

if (setvbuf(fp, absurd_buffer, _IOFBF, sizeof absurd_buffer) !
= 0) {
int e = errno;
puts(strerror(e ));
printf("Incorre ct type or size of buffer for log.txt.
Value of errno is %d.\n", e);
}
for (loop = 1; loop <= 10000000; loop++) {
fprintf(fp, "%u\n", fact(10));
}
fclose(fp);
}
return 0;
}

[James Kuyper]

c wrote:

On Dec 13, 3:46 am, "Default User" <defaultuse...@ yahoo.comwrote:

>c wrote:

>>On Dec 13, 2:51 am, Francine.Ne...@ googlemail.com wrote:
The answer to your question is 42.
What do you mean by 42..please give me more details..

<http://en.wikipedia.org/wiki/Answer_...se%2C_and_Ever
ything>

Brian

still don't know that do you guys mean by 42!!

If you followed up that wikipedia link, you should know that '42' is
meant as a nonsense answer to a question that hasn't been well-thought out.