#!/usr/bin/env perl
use strict;
use warnings;
use Time::HiRes qw( gettimeofday tv_interval );

for my $i (1 .. 100) {
    my $start = [gettimeofday];
    my $fibonacci_number = fibo($i);
    my $interval = tv_interval( $start, [gettimeofday]);
    print "fib($i)=$fibonacci_number  ($interval sec)\n";
}

sub fibo {
    my $num = shift;
    return 1 if $num<3;
    return fibo($num-1) + fibo($num-2);
}