LinuxQuestions.org - Perl for loop

- Programming (https://www.linuxquestions.org/questions/programming-9/)

- - Perl for loop (https://www.linuxquestions.org/questions/programming-9/perl-for-loop-832652/)

Hi,

I am quiet new to perl. I want to achieve the following result.

Find all the Pythagorean triples (a2 +b2=c2) where a,b,c are less than 1000. (a squared + b squared = c squared)

To achieve this goal. I created the following code.

#!/usr/bin/perl -w

for ($a = 1 ; $a < 1001 ; $a++)
{
for ($bi = 1 ; $b < 1001 ; $b++)
{
for ($b = 1 ; $b < 1001 ; $b++)
{
if ((($a * $a) + ($b * $b)) == ($c * $c))
{
print " value of (a) = $a \n";
print "value of (b) = $b \n";
print "value of (c) = $c \n";
}
}
}
}

When I execute this code, I get the following message.
…............
Use of uninitialized value in multiplication (*) at ./problem9 line 10.
Use of uninitialized value in multiplication (*) at ./problem9 line 10.
Use of uninitialized value in multiplication (*) at ./problem9 line 10.
Use of uninitialized value in multiplication (*) at ./problem9 line 10.
Use of uninitialized value in multiplication (*) at ./problem9 line 10.
Use of uninitialized value in multiplication (*) at ./problem9 line 10.
Use of uninitialized value in multiplication (*) at ./problem9 line 10.
Use of uninitialized value in multiplication (*) at ./problem9 line 10.
Use of uninitialized value in multiplication (*) at ./problem9 line 10.
Use of uninitialized value in multiplication (*) at ./problem9 line 10.
Use of uninitialized value in multiplication (*) at ./problem9 line 10.
Use of uninitialized value in multiplication (*) at ./problem9 line 10.
…........................

Can anyone please help me with this?

Thank you in advance.

K.Suthagar

I also tried.

#!/usr/bin/perl -w

my $a,$b,$c;

for ($a = 1 ; $a < 1001 ; $a++)
{
for ($bi = 1 ; $b < 1001 ; $b++)
{
for ($b = 1 ; $b < 1001 ; $b++)
{
if ((($a * $a) + ($b * $b)) == ($c * $c))
{
print " value of (a) = $a \n";
print "value of (b) = $b \n";
print "value of (c) = $c \n";

}
}
}
}

Hi,

You have a typo: for ($bi = 1 ; $b < 1001 ; $b++)

And there is no $c. Shouldn't the second for ($b = 1 ; $b < 1001 ; $b++) be for ($c = 1 ; $c < 1001 ; $c++)

Hope this helps.

Code:

#!/usr/bin/perl -w



for ( $a = 1 ; $a < 11 ; $a++ ) {

  for ( $b = 1 ; $b < 11 ; $b++ ) {

      for ( $c = 1 ; $c < 11 ; $c++ ) {

        if ( ( ( $a * $a ) + ( $b * $b ) ) == ( $c * $c ) ) {

            print "value of (a) = $a \n" ;

            print "value of (b) = $b \n" ;

            print "value of (c) = $c \n" ;

        }

      }

  }

}

Hi druuna,

Thank you for the help. I feel like a total idiot now. Sorry for wasting your time.

Thank You
K.Suthagar

Hi,

Don't worry about it, stuff like that happens ;)

BTW: You're welcome :)

Code:

#!/usr/bin/env ruby -w



a=(1..100).to_a

a.collect!{|x| x*x}

c=b=a

a.each_index do |x|

  (0..99).to_a.each do |y|

  print "a:#{Math.sqrt(a[x])}, b:#{Math.sqrt(b[y])}, c:#{a[x]+b[y]}\n" if c.include?(a[x] + b[y])

  end

end

Highly recommend you add

use strict;

as the first line of ALL your Perl programs. You'll thank me later, I promise :)
Do continue to use the -w switch as well, they catch different kinds of errors.
ie

Code:

#!/usr/bin/perl -w

use strict;

Try to minimise using global vars once you get into subroutines.
http://perldoc.perl.org/
http://www.perlmonks.org/?node=Tutorials