Perl Weekly Challenge 008

ch-1.pl

use strict;
use warnings;
##  
# Write a script that computes the first five perfect numbers. 
# A perfect number is an integer that is the sum of its positive 
# proper divisors (all divisors except itself). 
##
use constant PERFECT_COUNT => 5;

sub factor{
    my($n) = @_;
    my @factors = (1);
    foreach my $j (2..sqrt($n)){
        push @factors, $j if $n % $j == 0;
        push @factors, ($n / $j) if $n % $j == 0 && $j ** 2 != $n;
    }    
    return @factors;  
}

my $i = 2; 
my $count = 0; 
do{
    my @factors = factor($i);
    my $sum = unpack("%32I*", pack("I*", @factors));  
    if($sum == $i){
        print "$i ";   
        $count++;   
    }    
    $i++;   
}while($count < PERFECT_COUNT);
print "\n";   

ch-2.pl

use strict;
use warnings;
## 
# Write a function, "center", whose argument is a list of strings, which 
# will be lines of text. The function should insert spaces at the beginning 
# of the lines of text so that if they were printed, the text would be 
# centered, and return the modified lines.
## 
sub center{
    my @words = @_;  
    my @padded_words;  
    my %line_length; 
    my $max_length = -1; 
    my $center;  
    my $i = 0;  
    foreach my $line (@words){
        $line_length{$i} = do{
            $line =~ tr/ [a-z][A-Z]//;
        };  
        $max_length = $line_length{$i} if $line_length{$i} > $max_length; 
        $i++;
    }  
    $center = int($max_length / 2);
    for(my $i = 0; $i < @words; $i++){
        my $middle = int($line_length{$i} / 2);  
        my $padding = $center - $middle;  
        $padded_words[$i] = " " x $padding . $words[$i];   
    }   
    return @padded_words;  
}  

##
# Main
##  
my @words;  
do{
    local $/;
    @words = split(/\n/, <DATA>);  
};  
my @centered = center(@words);  
foreach my $w (@centered){
    print "$w\n";  
}  

__DATA__
This
is
a test of the
center function