From b122a46da523f5c95214d9b67d78011138e18df8 Mon Sep 17 00:00:00 2001
From: enigmagnetic <enigmagnetic@users.noreply.github.com>
Date: Fri, 11 Aug 2017 19:34:05 -0700
Subject: [PATCH] Lauren C calculator.rb

---
 calculator.rb | 81 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100644 calculator.rb

diff --git a/calculator.rb b/calculator.rb
new file mode 100644
index 0000000..4a3ee93
--- /dev/null
+++ b/calculator.rb
@@ -0,0 +1,81 @@
+# method to ensure user has entered a valid operator
+def validate_operator(operator)
+  valid_operators = ["+", "add", "-", "subtract", "*", "multiply", "/", "divide", "**", "exponent", "%", "modulo"]
+  # check input against array of operators, strip of any whitespace characters
+  until valid_operators.include?(operator)
+    puts "That is not a valid operator. This calculator accepts add (+), subtract (-), multiply (*), divide (/), exponent (**), and modulo (%)"
+    operator = gets.chomp.strip.downcase
+  end
+  # return the operator symbol for either symbol or word provided
+  case operator
+  when "add", "+"
+      return "+"
+    when "subtract", "-"
+      return "-"
+    when "multiply", "*"
+      return "*"
+    when "divide", "/"
+      return "/"
+    when "exponent", "**"
+      return "**"
+    when "modulo", "%"
+      return "%"
+  end
+end
+
+# method using regex to check that no alphabetic characters are used in number input
+def valid_num(string)
+  until !(string.match(/[a-z]/))
+    puts "Please enter an integer or decimal number: "
+    string = gets.chomp
+  end
+  # convert strings into floats and integers appropriately
+  if string.match(/[[:digit:]]\.[[:digit:]]/)
+    string = string.to_f
+  elsif string.match(/[[:digit:]]/)
+    string = string.to_i
+  end
+end
+
+# perform the operation with the 2 numbers provided
+def calculate(num_1, num_2, operator)
+  case operator
+  when "+"
+    return num_1 + num_2
+  when "-"
+    return num_1 - num_2
+  when "*"
+    return num_1 * num_2
+  when "/"
+    return num_1 / num_2
+  when "**"
+    return num_1 ** num_2
+  when "%"
+    return num_1 % num_2
+  end
+end
+
+# greet the user and get input
+puts "Welcome to the Calculator App"
+puts "Which operator would you like to use?"
+operator = gets.chomp.strip.downcase
+
+# make sure the user didn't accidentally hit enter without any input
+while operator.empty?
+  puts "That is not a valid operator. This calculator accepts add (+), subtract (-), multiply (*), divide (/), exponent (**), and modulo (%)"
+  operator = gets.chomp.strip.downcase
+end
+
+operator = validate_operator(operator)
+
+# get numbers and validate numbers
+puts "First number:"
+num_1 = valid_num(gets.chomp)
+
+puts "Second number:"
+num_2 = valid_num(gets.chomp)
+
+# pass needed arguments to the calculate method
+result = calculate(num_1, num_2, operator)
+# print equation and result
+puts "#{num_1} #{operator} #{num_2} = #{result}"