Constants in Ruby

Go supports _constants_ of character, string, boolean, and numeric values.

`const` declares a constant value.

```ruby
S = "constant"

You can use constants anywhere you can use a variable.

N = 500000000

Constant expressions perform arithmetic with arbitrary precision.

D = 3e20 / N
puts D

A numeric constant has no type until it’s given one, such as by an explicit conversion.

puts D.to_i

A number can be given a type by using it in a context that requires one, such as a variable assignment or function call. For example, here Math.sin expects a Float.

puts Math.sin(N)

To run the program, save the code in a file, for example, constants.rb, and use Ruby to execute it.

$ ruby constants.rb
6e+11
600000000000
-0.28470407323754404

Constant support in Ruby provides a straightforward way to handle immutable values.