Beginner's Programming Challenge 18

[roccivic]

It was very difficult to pick a winner, as all entries were good.

And the winner is....

... red_Marvin with his entry in PERL.

#!/usr/bin/env perl                 # just tell bash that it is a perl program
use warnings;                       # yell if I do something bad
use strict;                         # be less permissive than default
print "Enter key please:\n";        # text output
my $line = <>;                      # define a scalar line, and read one line
                                    # from stdin into it
my @k = split '', $line;             # define an array and split $line into
                                    # individual chars and store into it
print "Enter message please:\n";
my @m = split '', <>;               # shorter version of the above
print "Result:\n";


# start a for loop, the loop variable is $_ by default, and it will iterate
# through the values 0 to the index of the last value in @m minus 1:
# if we have the array @a, then $#a will be the index of the last item in @a
# ( we included '\n' when we read from stdin before, but we don't want it in
# the cipher, so for a string 'FOO\n' => ('F', 'O', 'O', '\n') we want to
# get the chars at 0, 1, 2 == 0..$#m-1 !!

for (0..$#m-1) {
print chr(
        (
            (
                ord(        # ord get's the ascii value of a char  
                    $m[$_]) # if we have the array @a $a[4] will get the item at position 4 in @a
                +ord(
                    $k[$_%$#k]) # modulus with length of key, since keylength can be < messagelength
                -130        # same as -65 -65 to make A<->0 B<->1 etc ('A' has 65 as ascii value)
            )       # now we have summed the numerical values of the message char and the right key char
            % 26    # to keep the value from overflowing
        ) +65       # to convert back so that A<->65 B<->66 etc
    );
}
print "\n";

Take care,
Rouslan

[red_Marvin]

Thankyou, I have come up with a new challenge, see link:
http://ubuntuforums.org/showthread.p...6#post10593716
I hope it is hard, but not too hard.
Good luck everyone!