Converting Celsius to Fahrenheit with Crystal

Previously in this series:

1. Converting Celsius to Fahrenheit with Python
2. TypeScript
3. Go
4. Ruby

Crystal?

Crystal is a general-purpose, object-oriented programming language. With syntax inspired by Ruby, it's a compiled language with static type-checking.

def c2f(c)
    c * 9.0 / 5 + 32;
end

def is_mirror(a, b)
    massage(a).reverse == massage(b)
end

def massage(n)
    if n < 10
        "0#{n}"
    elsif n >= 100
        massage(n - 100)
    else
        n.to_s
    end
end

def print_conv(c, f)
    puts "#{c}°C ~= #{f}°F"
end

(4...100).step(12).each do |c|
    f = c2f(c)
    if is_mirror(c, f.ceil.to_i)
        print_conv(c, f.ceil.to_i)
    elsif is_mirror(c, f.floor.to_i)
        print_conv(c, f.floor.to_i)
    else
        break
    end
end

And this is its diff with the Ruby version:

<     if is_mirror(c, f.ceil)
<         print_conv(c, f.ceil)
<     elsif is_mirror(c, f.floor)
<         print_conv(c, f.floor)
---
>     if is_mirror(c, f.ceil.to_i)
>         print_conv(c, f.ceil.to_i)
>     elsif is_mirror(c, f.floor.to_i)
>         print_conv(c, f.floor.to_i)

Run it like this:

crystal conversion.cr

or build and run:

crystal build -o conversion-cr conversion.cr
./conversion-cr

and the output becomes:

4°C ~= 40°F
16°C ~= 61°F
28°C ~= 82°F
40°C ~= 104°F
52°C ~= 125°F