From c35bf4a237c1a45e29891900b535448e4f580a2c Mon Sep 17 00:00:00 2001
From: lbristol88 <layla.bristol@gmail.com>
Date: Wed, 8 Aug 2018 10:11:24 -0700
Subject: [PATCH] Create calculator.rb

---
 calculator.rb | 109 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 109 insertions(+)
 create mode 100644 calculator.rb

diff --git a/calculator.rb b/calculator.rb
new file mode 100644
index 0000000..aec1fd5
--- /dev/null
+++ b/calculator.rb
@@ -0,0 +1,109 @@
+# calculator program that allows user to choose what operator, along with two numbers to calculate.
+
+# the program will run once while true and if the user wants to play again, they would need to type 'y' when prompted
+play_again = "y"
+
+
+# while will run true the first time and begin the program
+while play_again == "y"
+
+  puts """
+  Welcome to the calculator program. Which operator would you like to use?
+  1. add(+)
+  2. subtract(-)
+  3. multiply(*)
+  4. divide(/)
+
+  """
+
+# prompts the user to select which operator option they'd like to use.
+  print "Please choose one operator (name or symbol): "
+  user_input = gets.chomp
+
+# verifies if user enters in one of the defined options and if not, asks the user to re-enter their choice.
+  until %[add + subtract - multiply * divide /].include?(user_input)
+    print "Your input is invalid. Please try again. "
+    user_input = gets.chomp
+  end
+
+
+# user is asked to enter in their first integer
+  print "Enter the first number: "
+  first_number = gets.chomp
+
+# created an until loop to verify if user enters in an integer, and if not, prompts them to try again.
+# found this solution located here: https://stackoverflow.com/a/1236045 would like to know more on how 
+# rescue works or if there's a more ideal solution.
+
+  until (Integer(first_number) rescue false)
+      print "invalid input, please enter a number: "
+      first_number = gets.chomp
+  end
+
+
+# same code as first number prompt
+  print "Enter the second number: "
+  second_number = gets.chomp
+
+  until (Integer(second_number) rescue false)
+      print "invalid input, please enter a number: "
+      second_number = gets.chomp
+  end
+
+
+# saving the input variables to integer format so the calculations run correctly
+  first_number = first_number.to_i
+  second_number = second_number.to_i
+
+
+# created a case statment to run through the user_input operator choice and depending on 
+# which operator is selected, the calculation is completed and displayed for the user.
+  case user_input
+
+    when  "add", "+"
+
+      result_add = first_number + second_number
+      puts "Your result is: #{first_number} + #{second_number} = #{result_add}"
+
+    when  "subtract", "-"
+
+      result_sub = first_number - second_number
+      puts "Your result is: #{first_number} - #{second_number} = #{result_sub}"
+
+    when  "divide",  "/"
+
+# ensuring that if the user enters in 0 for their second number, the program asks for a new number if 
+# division operator is selected because you cannot divide by zero. 
+# Converts their number to a float to get accurate division result.
+        if second_number == 0
+            print "Cannot be divided by zero. Please re-enter your option: "
+            second_number = gets.chomp.to_f
+        end
+
+      result_div = first_number / second_number
+      puts "Your result is: #{first_number} / #{second_number} = #{result_div}"
+
+    when  "multiply",  "*"
+
+      result_multi = first_number * second_number
+      puts "Your result is: #{first_number} * #{second_number} = #{result_multi}"
+
+  end
+
+
+# asks the user if they want to run the program again
+  print "Want to play again? (y/n): "
+  play_again = gets.chomp
+
+# if 'y' is entered, the loop will run the program again, if neither y nor n is entered, 
+# the user will be asked to type again.
+  until play_again == "y" || play_again == "n"
+    print "invalid, please use 'y' or 'n'"
+    play_again = gets.chomp
+  end
+
+end
+
+puts
+# if n is chosen, the program ends and thanks the user.
+puts "Thanks for playing!"