```
print "enter a number: ";
$in = <>;
chomp $in;
print &prime($in);
print "\n";
sub prime{
for($i=2;$i<($_[0]/2+1);$i++){
if($_[0]%$i ==0){return "not prime\n"}
}
return "prime\n";
}
```

can anyonet tell me, what program do i use to make this code work?..

i just found it on the internet while searching a formula for evaluating if a number is prime or composite..

i didn't see any program they tell to use this code..