#!/usr/bin/env perl
use utf8;
###############################################################################
# This program computes the number of primes function π(x)
# using an estimate formula.
# 
# Copyright © 2021 Richard Lesh.  All rights reserved.
###############################################################################

use POSIX qw(floor);
use Utils;
use strict;
use warnings;

sub π {
    my ($x) = @_;
    return floor($x / (log($x) - 1.0) + 0.5);
}

MAIN:
{
    binmode(STDOUT, ":utf8");
    binmode(STDERR, ":utf8");
    binmode(STDIN, ":utf8");
    my $x = 10;
    for (my $i = 2; $i <= 9; ++$i) {
        $x *= 10;
        print Utils::messageFormat("π(\{0:d\}) = \{1:d\}", $x, π($x)), "\n";
    }
}