not a homework question

[Three Headed Monkey]

write a program in "C" language that computes 9^(8^(7^(6^(5^( 4^(3^(2^1)))))) )

I tried

#include <stdio.h>

int pow(int n)
{
int i,power;
power=n;
for(i=0;i<n;i=i +1)
power=power*pow er;
return power;
}

void main()
{
int result;
char ignore;
result= pow(9,pow(8,pow (7,pow(6,pow(5, pow(4,pow(3,pow (2,1))))))));
printf("\nresul t is %d", result);
printf("\nPress ENTER");
gets(&ignore);
}
but it does not work.

how to do that in "C" standard language?

I am using lcc-win32 compiler & windows 98.

help!

[Bartc]

"Three Headed Monkey" <fo************ ****@yahoo.comw rote in message
news:12******** **********@aioe .org...

>
write a program in "C" language that computes
9^(8^(7^(6^(5^( 4^(3^(2^1)))))) )

So if it's not homework, where does the problem come from? I suspect you
don't really to know the answer to this.

The algorithm can be done neatly in C using integer arithmetic. You were on
the right lines with your code, but you should have tested with a smaller N.

However, it is likely to overflow above N=4. Using bigger ints will help a
little but
will not come near N=9. This is my version tested to N=4:
#include <stdio.h>

int solve(int);

int main(void)
{int n,result;

n=4;

result=solve(n) ;

printf("Answer for N = %d is %d\n",n,result) ;

}

int solve(int n)
{
int i,x,a;

if (n<=1) return 1;

x=solve(n-1);

a=n;
for (i=1; i<x; ++i) a*=n;

return a;

}

--
Bart

[Barry Schwarz]

On Tue, 11 Mar 2008 22:25:01 -0700 (PDT), Brice Rebsamen
<br*********@gm ail.comwrote:

>On Mar 12, 12:57 pm, Three Headed Monkey
<four_headed_m [e-mail] wrote:

>write a program in "C" language that computes 9^(8^(7^(6^(5^( 4^(3^(2^1)))))) )

I tried

#include <stdio.h>

int pow(int n)
{
int i,power;
power=n;
for(i=0;i<n;i=i +1)
power=power*pow er;
return power;

}

void main()
{
int result;
char ignore;
result= pow(9,pow(8,pow (7,pow(6,pow(5, pow(4,pow(3,pow (2,1))))))));
printf("\nresul t is %d", result);
printf("\nPress ENTER");
gets(&ignore);

}

but it does not work.

how to do that in "C" standard language?

I am using lcc-win32 compiler & windows 98.

help!

First, you may want to have the pow function take 2 arguments: int
pow(int a, int n) { ... }
Second, the pow function defined in math.h does the job for you,
except that it deals with doubles: float pow(double a, double n)
returns a to the power of n as a float. So if you want to deal with

Close. pow returns a double, not a float.

>integers you have to convert the result.
Finally you may want to use a loop to do this. It'd look like this:

#include <math.h>
#include <stdio.h>
int main(){
double res=1;
int n;
for( n=2; n<=9; n++ )
res = pow((double)n,r es);

The cast is superfluous.

printf("res=%f\ n",res);

%g might be better.

return 0;
}

Don't forget to link with the math library when compiling (-lm)

A system specific issue that may or may not be applicable to the OP.

>
However this might overflow, resulting in res reaching inf. You can
try using long double and powl... Or more complicated stuff. Any idea
of what the resulting number might be?

Remove del for email

[Keith Thompson]

Noob <root@localhost writes:

Keith Thompson wrote:

[...]

>u7, u8, and u9 are Really Really Big (but still tiny compared to the
largest numbers that have actually been used in mathematics).

Are you referring to Graham's number?
World Champion largest number! ^_^

http://en.wikipedia.org/wiki/Graham%27s_number

Yup, that's the one I had in mind.

Graham's number is an upper bound on a number of dimensions for an
n-dimensional hypercube with certain characteristics . Graham and
Rothschild's paper provided a lower bound of 6; Martin Gardner called
this "perhaps the worst smallest-upper-bound ever discovered". (More
recently, the lower bound has been shown to be at least 11.)

So if you need to work with numbers that are too big to represent in
any arithmetic type in C, you can either come up with an alternate
representation (it wouldn't be hard to write C code that could
manipulate Knuth's up-arrow notation, used to describe Graham's
number), or improve your algorithm so you can use smaller numbers.
(There, it's topical!)

But consider this ...

(drum roll please)

GRAHAM'S NUMBER PLUS ONE!!!!

I win.

--
Keith Thompson (The_Other_Keit h) <ks***@mib.or g>
Nokia
"We must do something. This is something. Therefore, we must do this."
-- Antony Jay and Jonathan Lynn, "Yes Minister"

[CBFalconer]

Three Headed Monkey wrote:

>
write a program in "C" language that computes
9^(8^(7^(6^(5^( 4^(3^(2^1)))))) )

Since 2 xor 1 is identically zero, that value suffices.

x = 0;

--
[mail]: Chuck F (cbfalconer at maineline dot net)
[page]: <http://cbfalconer.home .att.net>
Try the download section.
--
Posted via a free Usenet account from http://www.teranews.com

[Coos Haak]

Op Wed, 12 Mar 2008 00:33:53 -0500 schreef CBFalconer:

Three Headed Monkey wrote:

>>
write a program in "C" language that computes
9^(8^(7^(6^(5^( 4^(3^(2^1)))))) )

Since 2 xor 1 is identically zero, that value suffices.

Since when? I get 3.

x = 0;

The value of the expression is 1.
--
Coos

[Antoninus Twink]

On 13 Mar 2008 at 21:24, Coos Haak wrote:

Op Wed, 12 Mar 2008 00:33:53 -0500 schreef CBFalconer:

>Three Headed Monkey wrote:

>>>
write a program in "C" language that computes
9^(8^(7^(6^(5^( 4^(3^(2^1)))))) )

Since 2 xor 1 is identically zero, that value suffices.

Since when? I get 3.

> x = 0;

The value of the expression is 1.

CBF is a moaning old fart with no discernible technical knowledge or
skill. If you spend your time correcting his technical errors, you'll
waste a huge amount of time for no reward.

[Doug Miller]

In article <17************ ****@aioe.org>, Three Headed Monkey <fo************ ****@yahoo.comw rote:

>It probably beyond my imagination,

Obviously.

>but when printing this number
on screen, how much time can I expect?

Considerably more than the age of the universe.

>If printed on paper, how many sheets will it needs?

There is not enough paper in existence to print this number. There has not
been enough paper manufactured since paper was invented to print this number.
There will not be enough paper manufactured between now and the end of time to
print this number. What part of "there are more digits in this number than
there are atoms in the universe" are you having trouble understanding?

--
Regards,
Doug Miller (alphageek at milmac dot com)

It's time to throw all their damned tea in the harbor again.

[Hans Schneider]

Doug Miller schreibt:

In article <17************ ****@aioe.org>, Three Headed Monkey
<fo************ ****@yahoo.comw rote:

>>It probably beyond my imagination,

Obviously.

>>but when printing this number
on screen, how much time can I expect?

Considerably more than the age of the universe.

>>If printed on paper, how many sheets will it needs?

There is not enough paper in existence to print this number. There has not
been enough paper manufactured since paper was invented to print this
number. There will not be enough paper manufactured between now and the
end of time to print this number. What part of "there are more digits in
this number than there are atoms in the universe" are you having trouble
understanding?

You should always save paper and print on both sides.

[Wolfgang Riedel]

Richard Heathfield schrieb:

Three Headed Monkey said:

>>write a program in "C" language that computes
9^(8^(7^(6^(5 ^(4^(3^(2^1)))) )))

#include <stdio.h>

int main(void)
{
printf("%d\n",
9^(8^(7^(6^(5^( 4^(3^(2^1)))))) ));
return 0;
}

your system has a 255624-bit integer type?

[Richard Heathfield]

Wolfgang Riedel said:

Richard Heathfield schrieb:

>Three Headed Monkey said:

>>>write a program in "C" language that computes
9^(8^(7^(6^( 5^(4^(3^(2^1))) ))))

#include <stdio.h>

int main(void)
{
printf("%d\n",
9^(8^(7^(6^(5^( 4^(3^(2^1)))))) ));
return 0;
}

your system has a 255624-bit integer type?

Well, not unless I use my bignum library - but it isn't necessary for this
program. (Try it!)

--
Richard Heathfield <http://www.cpax.org.uk >
Email: -http://www. +rjh@
Google users: <http://www.cpax.org.uk/prg/writings/googly.php>
"Usenet is a strange place" - dmr 29 July 1999