my (@thetas, @press);
my ($i);

use strict;
use warnings;

my $outfilename = "pot_temp.txt";# define an output filename
open(TFILE,">$outfilename");

print "What is the temperature (K)? \n";
my $T = <STDIN>;
chomp ($T);

for ($i=500, $i=900 , $i += 100) 
	{
	my $theta = $T*((1013/$i)**(287/1004));
	push (@press, $i);
	push (@thetas,$theta);
	}
	
print TFILE "A T of $T results in thetas of @thetas at the pressure levels @press \n";