Challenge 3: Sketch a Tiny Gem — Solution

# temp_converter.gemspec
Gem::Specification.new do |spec|
  spec.name        = "temp_converter"
  spec.version      = "0.1.0"
  spec.authors      = ["Philip Osztromok"]
  spec.summary      = "Converts temperatures between Celsius and Fahrenheit."
  spec.files        = ["lib/temp_converter.rb"]
end

# lib/temp_converter.rb
module TempConverter
  def self.celsius_to_fahrenheit(c)
    (c * 9.0 / 5) + 32
  end
end

# Usage, once installed:
# require "temp_converter"
# TempConverter.celsius_to_fahrenheit(100)  # => 212.0

=begin
Notes:
- spec.name, spec.version, spec.authors, and spec.summary are the minimum
  metadata RubyGems needs to identify and describe the gem — this mirrors
  the "name"/"version"/"description" fields in a PHP composer.json or a
  Python pyproject.toml's [project] section.
- spec.files lists exactly which files get packaged into the built .gem —
  only lib/temp_converter.rb here, since that's the gem's entire
  implementation.
- celsius_to_fahrenheit is defined with self., making it a class method
  (Course 1, Chapter 6) callable directly as TempConverter.celsius_to_
  fahrenheit(...) with no instance required, appropriate for a small,
  stateless utility gem like this one.
- (c * 9.0 / 5) uses 9.0 rather than plain 9 deliberately, to force float
  division and avoid the Course 1 Chapter 2 integer-division gotcha that
  would otherwise silently truncate the result.
=end