Thanks... sorry for the stupid mistake. Here's the corrected code:
#!/usr/bin/perl w
# summation examples from SICP done in Perl
use strict;
use warnings;
my $result = &sum_integers(1, 3);
print "sum_integers(1, 3) equals $result\n";
$result = &cube(3);
print "cube(3) equals $result\n";
$result = &sum_cubes(1, 3);
print "sum_cubes(1, 3) equals $result\n";
$result = &sum_cubes2(1, 3);
print "sum_cubes2(1, 3) equals $result\n";
sub sum_integers {
my ($a, $b) = @_;
if ($a > $b) { return(0); }
else { return( $a + &sum_integers(($a + 1), $b) ); }
}
sub cube {
my ($a) = @_;
return( $a * $a * $a );
}
sub sum_cubes {
my ($a, $b) = @_;
if ($a > $b) { return(0); }
else { return( &cube($a) + &sum_cubes(($a + 1), $b) ); }
}
sub sum {
my ($term, $a, $next, $b) = @_;
if ($a > $b) { return(0); }
else { return( $term>($a) + &sum( $term, ($next>($a)), $next, $b
+) ); }
}
sub inc {
my ($n) = @_;
return( $n + 1 );
}
sub sum_cubes2 {
my ($a, $b) = @_;
return( &sum(\&cube, $a, \&inc, $b) );
}
