my %scale =
Celcius => { factor => 1 , offset => -273.15 },
Rankine => { factor => 1.8, offset => 0 },
Fahrenheit => { factor => 1.8, offset => -459.67 },
;
my $kelvin = +prompt "Enter a temperature in Kelvin: ";
die "No such temperature!" if $kelvin < 0;
for %scale.sort {
printf "%12s: %7.2f\n", .key, $kelvin * .value<factor> + .value<offset>;
}
Output:
Enter a temperature in Kelvin: 21
Celcius: -252.15
Fahrenheit: -421.87
Rankine: 37.80
Alternative version that accepts the input in any of the four scales:
while my $answer = prompt 'Temperature: ' {
my $k = do given $answer {
when s/:i C $// { $_ + 273.15 }
when s/:i F $// { ($_ + 459.67) / 1.8 }
when s/:i R $// { $_ / 1.8 }
when s/:i K $// { $_ }
default { $_ }
}
say " { $k }K";
say " { $k - 273.15 }℃";
say " { $k * 1.8 - 459.67 }℉";
say " { $k * 1.8 }R";
}