On 10/23/07, camotito <[EMAIL PROTECTED]> wrote: > I was just implementing this small program for calculating the line- > equation, given two points. > Just in case you don't remind this equation.... y = slope * x + b. > First I calculate the slope and then b: > > $slope = ($ARGV[1] - $ARGV[3]) / ($ARGV[0] - $ARGV[2]); > $b = $ARGV[1] - ($ARGV[0] * $slope); > print "\n$ARGV[1] = $slope * $ARGV[0] + $b\n";
It's easier to read, write, and maintain code that uses names instead of indices. So I'd re-write your code so far like this: use strict; use warnings; # @ARGV holds two points (two xy pairs) my($x1, $y1, $x2, $y2) = @ARGV; my $slope = ($y1 - $y2) / ($x1 - $x2); my $b = $y1 - ($x1 * $slope); print "\n"; print "$y1 = $slope * $x1 + $b\n"; > For this input : > > perl my_program 16.81 16.57 0 0 > > It gives me this result : > > 16.57 = 0.985722784057109 * 16.81 + 0 > > Clearly b can be 0 only if the slope is 1. One must pay special attention to those points a mathematician describes as "clear". :-) You must have meant to say, clearly, b can be 0 only if the line passes through the origin. But check that sort of detail with your algebra teacher or in a mathematics forum; perl is doing what you're asking of it. Cheers! --Tom Phoenix Stonehenge Perl Training -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/
