41 lines
674 B
Perl
41 lines
674 B
Perl
|
#!/usr/bin/env perl
|
||
|
|
||
|
# prime number calculation
|
||
|
# author: david@socialnerds.org
|
||
|
|
||
|
my $num = 3;
|
||
|
print "highest prime number: ";
|
||
|
chomp(my $maxnum = <STDIN>);
|
||
|
my $count = 2;
|
||
|
|
||
|
print "2\n3\n";
|
||
|
|
||
|
while ( $num <= $maxnum )
|
||
|
{
|
||
|
$i=3;
|
||
|
while ( $i <= int($num**(1/2)+1) )
|
||
|
{
|
||
|
if ( $i != 1 && $i < $num && $i%2 != 0 )
|
||
|
{
|
||
|
if ( $num % $i != 0 ) {
|
||
|
$probably = "true"
|
||
|
} else {
|
||
|
$probably = "false";
|
||
|
last;
|
||
|
}
|
||
|
}
|
||
|
$i += 2;
|
||
|
}
|
||
|
|
||
|
if ( $probably eq "true" )
|
||
|
{
|
||
|
print "$num\n";
|
||
|
$count++;
|
||
|
}
|
||
|
$num += 2;
|
||
|
}
|
||
|
|
||
|
print "prime number count: $count\n";
|
||
|
|
||
|
|