Quadratic equation in Perl

Example for versions rakudo-2010.08

This example differs from one in Perl 5 in two major ways: the way user input is read and results are printed, and the way all variables have to be predeclared with my keyword before using them. Note that explicit declaration of variable type stays optional. 

my $A = $*IN.get;
if ($A == 0) {
    say "Not a quadratic equation.";
}
else {
    my $B = $*IN.get;
    my $C = $*IN.get;
    my $D = $B * $B - 4 * $A * $C;
    if ($D == 0) {
        say "x = ", -0.5 * $B / $A;
    }
    else {
        if ($D > 0) {
            say "x1 = ", 0.5*(-$B + sqrt($D))/$A, "\nx2 = ", 0.5*(-$B - sqrt($D))/$A
        }
        else {
            say "x1 = (", -0.5*$B/$A, ",", 0.5*sqrt(-$D)/$A, ")\nx2 = (", -0.5*$B/$A, ",", -0.5*sqrt(-$D)/$A, ")\n"
        }
    }
}