From 0ea222c168a87e69cc476901923c584e7c4694e5 Mon Sep 17 00:00:00 2001
From: Spatterjaaay <aja.pursova@gmail.com>
Date: Thu, 9 Feb 2017 23:26:49 -0800
Subject: [PATCH 1/2] Create Calculator.rb

---
 Calculator.rb | 76 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 76 insertions(+)
 create mode 100644 Calculator.rb

diff --git a/Calculator.rb b/Calculator.rb
new file mode 100644
index 0000000..e95613c
--- /dev/null
+++ b/Calculator.rb
@@ -0,0 +1,76 @@
+# checks whether user wrote correct operation
+def math()
+  operations = ["add", "+", "subtract", "-", "multiply", "*", "divide", "/", "raise", "^", "modulo", "%"]
+  symbol = gets.chomp
+  until operations.include?(symbol)
+    print "That's not a valid entry, please try again: "
+    symbol = gets.chomp
+  end
+  return symbol
+end
+
+# beginning of the code
+print "What kind of math would you like to perform? "
+command = math()
+
+# checks whether user wrote a number
+def read_number(prompt)
+  error_msg_1 = "Uh oh, invalid value. Please try again."
+  number = nil
+  while number == nil
+    print prompt
+    user_input = gets.chomp
+    if user_input.include?(".")
+      # Integer() will convert input to a number or it will throw an error
+      # that will be caught by the rescue clause if input is not a number
+      # rescue prints error message and continues execution of the code
+      number = Float(user_input) rescue puts(error_msg_1)
+    else
+      number = Integer(user_input) rescue puts(error_msg_1)
+    end
+  end
+  return number
+end
+
+first_number = read_number("What is the first number? ")
+
+second_number = read_number("What is the second number? ")
+
+# performs calculation based on user's input
+if command == "add" || command == "+"
+  result = first_number + second_number
+  command = "+"
+elsif command == "substract" || command == "-"
+  result = first_number - second_number
+  command = "-"
+elsif command == "multiply" || command == "*"
+  result = first_number * second_number
+  command = "*"
+elsif command == "divide" || command == "/"
+  # catches the division by 0 that throws an error
+  # begin contains code that potentially may throw an error
+  begin
+    result = first_number / second_number
+    # rescue catches and handles error
+    # prints a message
+  rescue
+    puts("Oh no. We cannot divide by 0.")
+    # terminates the program
+    exit
+  end
+elsif command == "raise" || command == "^"
+  result = first_number ** second_number
+  command = "^"
+elsif command == "modulo" || command == "%"
+  command = "%"
+  begin
+    result = first_number % second_number
+  rescue
+    puts("Oh no. We cannot divide by 0.")
+    exit
+  end
+  command = "%"
+end
+
+# prints the result based on the user input
+puts "#{first_number} #{command} #{second_number} = #{result}"

From 1ed443343b66749689aa6159e7ef9149feb4f687 Mon Sep 17 00:00:00 2001
From: Spatterjaaay <aja.pursova@gmail.com>
Date: Thu, 9 Feb 2017 23:48:53 -0800
Subject: [PATCH 2/2] Changed if statements to case/when

---
 Calculator.rb | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/Calculator.rb b/Calculator.rb
index e95613c..e66e7a8 100644
--- a/Calculator.rb
+++ b/Calculator.rb
@@ -37,16 +37,17 @@ def read_number(prompt)
 second_number = read_number("What is the second number? ")
 
 # performs calculation based on user's input
-if command == "add" || command == "+"
+case command
+when "add", "+"
   result = first_number + second_number
   command = "+"
-elsif command == "substract" || command == "-"
+when "substract", "-"
   result = first_number - second_number
   command = "-"
-elsif command == "multiply" || command == "*"
+when "multiply", "*"
   result = first_number * second_number
   command = "*"
-elsif command == "divide" || command == "/"
+when "divide", "/"
   # catches the division by 0 that throws an error
   # begin contains code that potentially may throw an error
   begin
@@ -58,10 +59,10 @@ def read_number(prompt)
     # terminates the program
     exit
   end
-elsif command == "raise" || command == "^"
+when "raise", "^"
   result = first_number ** second_number
   command = "^"
-elsif command == "modulo" || command == "%"
+when "modulo", "%"
   command = "%"
   begin
     result = first_number % second_number