Using sqrt in a korn shell

snowman81 · 11-30-2008, 06:11 PM

I have a program I wrote for a class like a year ago that I am messing around with. It is really simple, just getting a number and doing the square and the square root and things like that. I know it worked before because I turned it in and I got an "A" but now it doesn't. I am using the latest ubuntu live cd that didn't come with a korn shell so I had to install pdksh which is a public domain version.

The line in the script is this

Code:

FINAL2=$((sqrt(FINAL1)))

and this is the error it is giving me

Code:

./korn.sh[43]: sqrt(FINAL1): unexpected `(

Can anyone help?

PS. Also, either I can't remember how to use the code tags or it isn't working in the preview post window. Am I just doing it wrong?

ghostdog74 · 11-30-2008, 06:48 PM

awk

Code:

# awk 'BEGIN{print sqrt(4)}'
2

or using bc

Code:

 # echo "sqrt(4)" | bc
2

makyo · 12-01-2008, 06:30 AM

Hi.

Building on ghostdog74's idea:

Code:

#!/usr/bin/env ksh

# @(#) s1       Demonstrate floating point in pdksh.
# pdksh does not support floating-point directly.

echo
export LC_ALL=C
echo "Environment: LC_ALL = $LC_ALL"
echo "(Versions displayed with local utility \"version\")"
version >/dev/null 2>&1 && version "=o" $(_eat $0 $1) bc
echo

isqrt()
{
echo "sqrt($1)" | bc
}

sqrt()
{
echo "scale=3 ; sqrt($1)" | bc
}

echo " Integer:"
for i in 2 7 16 20
do
  t=$( isqrt $i )
  printf " Integer: square root of %d is %d\n" $i $t
done

echo
echo " Float:"
for i in 2 7 16 20
do
  t=$( sqrt $i )
  printf " Float: square root of %f is %f\n" $i $t
done

exit 0

Producing:

Code:

% ./s1

Environment: LC_ALL = C
(Versions displayed with local utility "version")
Linux 2.6.11-x1
pdksh 5.2.14 99/07/13.2
bc 1.06

 Integer:
 Integer: square root of 2 is 1
 Integer: square root of 7 is 2
 Integer: square root of 16 is 4
 Integer: square root of 20 is 4

 Float:
 Float: square root of 2.000000 is 1.414000
 Float: square root of 7.000000 is 2.645000
 Float: square root of 16.000000 is 4.000000
 Float: square root of 20.000000 is 4.472000

Best wishes ... cheers, makyo

snowman81 · 12-01-2008, 12:51 PM

I probably should have mentioned that one of the original requirements was to not use an outside program like bc. But the function in awk does work and I didn't know you could do that. So it got fixed and I learned something new. Sweet.

testing code tag

Code:

 blah blah

So that's how you do it... I'm dumb.

makyo · 12-01-2008, 02:45 PM

Hi.

Quote:

Originally Posted by snowman81

I probably should have mentioned that one of the original requirements was to not use an outside program like bc. But the function in awk does work ...

Are you saying that you could not use bc because it is an outside program -- presumably external to the shell -- but that the use of awk is permissible? ... cheers, makyo

snowman81 · 12-01-2008, 02:48 PM

Hmmm, I suppose you're right. I honestly don't remember what he told me. Meh, I suppose it doesn't matter anymore since I'm not under any restrictions anymore. Thanks for the help.