Merge pull request #136 from msaf9/master

weight conversions feature implementation

Author: vbrazo

DIRECTORY.md

@@ -10,6 +10,7 @@
 
 ## Conversions
   * [Temperature Conversions](https://github.com/TheAlgorithms/Ruby/blob/master/conversions/temperature_conversions.rb)
+  * [Weight Conversions](https://github.com/TheAlgorithms/Ruby/blob/master/conversions/weight_conversions.rb)
 
 ## Data Structures
   * Arrays

conversions/weight_conversions.rb

@@ -0,0 +1,106 @@
+# A ruby program for weight conversions
+
+module WeightConversion
+  # Kilogram -> Gram = (kilogram_value * 1000) grams
+  def self.kilogram_to_gram(kilogram_input)
+    raise StandardError unless Integer === kilogram_input
+
+    gram = kilogram_input * 1000
+
+    "#{kilogram_input} kg = #{gram} g"
+  end
+
+  # Gram -> Kilogram = (gram_value / 1000) kilograms
+  def self.gram_to_kilogram(gram_input)
+    kilogram = gram_input / 1000
+
+    "#{gram_input} g = #{kilogram} kg"
+  end
+
+  # Pound -> Ounce = (pound_value * 16) oz
+  def self.pound_to_ounce(pound_input)
+    ounce = pound_input * 16
+
+    "#{pound_input} lb = #{ounce} oz"
+  end
+
+  # Ounce -> Pound = (ounce_value / 16) lb
+  def self.ounce_to_pound(ounce_input)
+    pound = ounce_input / 16
+
+    "#{ounce_input} oz = #{pound} lb"
+  end
+
+  # Kilogram -> Pound = (kilogram_input * 2.205) lb
+  def self.kilogram_to_pound(kilogram_input)
+    pound = (kilogram_input * 2.205).round(2)
+
+    "#{kilogram_input} kg = #{pound} lb"
+  end
+
+  # Pound -> Kilogram = (pound_input / 2.205) kg
+  def self.pound_to_kilogram(pound_input)
+    raise StandardError unless Integer === pound_input
+
+    kilogram = (pound_input / 2.205).round(2)
+
+    "#{pound_input} lb = #{kilogram} kg"
+  end
+end
+
+# 
+# Valid inputs
+# 
+
+puts WeightConversion.kilogram_to_gram(2)
+# 2 kg = 2000 g
+puts WeightConversion.gram_to_kilogram(3000)
+# 3000 g = 3 kg
+puts WeightConversion.pound_to_ounce(16)
+# 16 lb = 256 oz
+puts WeightConversion.ounce_to_pound(16)
+# 16 oz = 1 lb
+puts WeightConversion.kilogram_to_pound(1)
+# 1 kg = 2.21 lb
+puts WeightConversion.pound_to_kilogram(100)
+# 100 lb = 45.35 kg
+
+# 
+# Invalid inputs
+# 
+
+begin
+  puts WeightConversion.kilogram_to_gram("a")
+rescue StandardError
+  puts "Error: Please provide number only!"
+end
+
+begin
+  puts WeightConversion.kilogram_to_gram("3000")
+rescue StandardError
+  puts "Error: Please provide number only!"
+end
+
+begin
+  puts WeightConversion.kilogram_to_gram("16")
+rescue StandardError
+  puts "Error: Please provide number only!"
+end
+
+begin
+  puts WeightConversion.kilogram_to_gram("x ")
+rescue StandardError
+  puts "Error: Please provide number only!"
+end
+
+begin
+  puts WeightConversion.kilogram_to_gram("weight")
+rescue StandardError
+  puts "Error: Please provide number only!"
+end
+
+begin
+  puts WeightConversion.kilogram_to_gram("100")
+rescue StandardError
+  puts "Error: Please provide number only!"
+end