From 97e3e62af152c22dc3f3e67713d5a517d4605ddb Mon Sep 17 00:00:00 2001
From: kee nam <nam.keeyeon@gmail.com>
Date: Fri, 11 Aug 2017 02:32:48 -0700
Subject: [PATCH] Create calculator.rb

---
 calculator.rb | 108 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 108 insertions(+)
 create mode 100644 calculator.rb

diff --git a/calculator.rb b/calculator.rb
new file mode 100644
index 0000000..498e180
--- /dev/null
+++ b/calculator.rb
@@ -0,0 +1,108 @@
+# Meth(od) collection
+def get_operator
+  text2sign = {
+    "add" => "+",
+    "subtract" => "-",
+    "multiply" => "*",
+    "divide" => "/",
+    "power" => "**",
+    "remainder" => "%"
+  }
+  op = 0
+  loop do
+    puts "\nWhat's the core operation you want to do?"
+    op = gets.chomp.downcase
+    if op.length == 1 || op.length == 2
+      text2sign.each do |key, value|
+        if op == value
+          return op = value
+        end
+      end
+      puts "Come again?"
+    elsif op.length > 1
+      text2sign.each do |key, value|
+        if op == key
+          return op = value
+        end
+      end
+      puts "I don't think that's right."
+    end
+  end
+end
+
+def get_half
+  input = 0
+  loop do
+    puts "\nEnter a number or parenthetical expression."
+    input = gets.chomp
+    string = input.to_s
+
+    if string.match(/\(/) == nil
+      if string.to_i == 0 && string.to_f == 0 && string != "0"
+        puts "\nWe need a mathy input, ok?"
+      elsif string.to_i == string.to_f
+        return string.to_i
+      else
+        if string.to_s == string.to_f.to_s
+          return string.to_f
+        end
+      end
+    else
+      split_string = string.gsub(" ", "").split(/(\d+\.?\d*)/)
+      split_string = split_string.delete_if {|x| x == "(" || x == ")"}
+      expression = split_string.join(" ")
+      check = eval(expression)
+      if check.class == Float || check.class == Integer
+        return check
+      end
+    end
+  end
+end
+
+def zero_check(num2,op)
+  loop do
+    if (op == "/" || op == "%" ) && num2 == 0
+      puts "Oh no, we can't allow division by zero."
+      num2 = get_half
+    else
+      return num2
+    end
+  end
+end
+
+def clarify_result(num1, num2, op)
+  num1 = num1.to_f
+  num2 = num2.to_f
+  result = num1.send(op,num2)
+  if result.to_i == result.to_f
+    return result.to_i
+  else
+    return result
+  end
+end
+
+# Explanation of calculator
+functions = [
+  {define: "For ADDITION, enter ", sign: "+", text: "add" },
+  {define: "For SUBTRACTION, enter ", sign: "-", text: "subtract" },
+  {define: "For MULTIPLICATION, enter ", sign: "*",  text: "multiply" },
+  {define: "For DIVISION, enter ", sign: "/", text: "divide" },
+  {define: "For EXPONENTS, enter ", sign: "**", text: "power" },
+  {define: "For REMAINDERS, enter ", sign: "%", text: "remainder" }
+]
+puts "\n========== Welcome to the calculator =========="
+functions.each do |function|
+  printf("%-28s %-4s %-3s %-10s\n", function[:define], function[:sign], "or", function[:text])
+end
+puts "================================================="
+
+# Get all user inputs and check for zero division
+op = get_operator
+num1 = get_half
+num2 = get_half
+num2 = zero_check(num2, op)
+result = clarify_result(num1, num2, op)
+
+# Display calculation to user
+puts "\n=========== Your Calculation Results ============"
+puts("\n  #{num1}   #{op}   #{num2}   =   #{result}\n\n")