#!/usr/bin/perl
use warnings;
use strict;
use feature "state"; 

sub sum # TERM A NEXT B
{	
	state $sum;
	my ($TERM, $A, $NEXT, $B) = @_;
	if ($A>$B){ 
		my $temp=$sum;
		$sum=0;
		return $temp ;
		}
	$sum+=&{$TERM}($A);
	sum( $TERM, &{$NEXT}($A) ,$NEXT, $B);
}

sub identity{
	shift;
	}

sub square{
	((shift)**2);
	}

sub sumint { sum(\&identity,shift,sub {((shift)+1)},shift)}

sub sumsq { sum(\&square,shift,sub {((shift)+1)},shift)}

#a normal sum from 3-5
print sumint(3,5) . "\n";
#a sum of squares from 3-5
print sumsq(3,5) . "\n";