about_math.pl

#!/usr/bin/perl
=pod
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=cut

package Perl::Koans::Math;
use warnings;

use lib './lib';
use Perl::Koans;

################
# your code goes below this line

sub about_math {
    # about_math() 
    # TODO break this up into distinct subs?
    
    # increment/decrement
    my $foo = 10;
    
    is ($foo++, __, "++ increments a variable by 1");
    is ($foo--, __, "-- decrements a variable by 1");
    
    my $bar = 20;
    
    $bar += 10;
    is ($bar, __, "+= increments and assigns");
    
    $bar -= 10;
    is ($bar, __, "-= decrements and assigns");
    
    $bar *= 2;
    is ($bar, __, "*= multiples and assigns");
    
    $bar /= 2;
    is ($bar, __, "/= divides and conquers"); # couldn't help myself. since this is rarely (if ever) used, not sure we should keep it
    
    # modulus
    my $baz = 100;
    is ($baz % 50, 0,  "% provides the modulus");
    is ($baz % 10, __, "% provides the modulus - part 2"); # TODO better hint
    
    my $even = __;
    my $odd  = __;
    is ($even % 2, 1, "modulus is often used to determine even/odd");
    is ($odd  % 2, 0, "modulus is often used to determine even/odd - part 2");
    
    # power of / sqrt
    my $base = 3;
    is ($base ** 2, _, "** raises first operand to second operand"); # TODO better hint
    is ($base ** __, 27, "** raises first operand to second operand - part 2");
    
    $base = 25;
    is (sqrt($base), __, "sqrt() gives the square root of the operand");
    is (__, 8, "sqrt() gives the square root of the operand -- part 2");
    
    return (Perl::Koans::get_return_code()); 
}


# your code goes above this line
################

unless (caller(0)) {
    run(@ARGV) or print_illumination();
    exit();
}

sub run {
    # run() -- runs all functions in this module
    my $results = 0;
    
    $results += about_math();
    
    return ($results) ? bail($results) : $results;
}


1;