# 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"
}
}
}
```

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