Queues - Janice Lichtman -Calculator

calculator.rb

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+#Janice Lichtman's Calulator Program
+
+
+#A method for testing whether user input is a number
+def number_test(number)
+  return Float(number) != nil rescue false
+end
+
+#A method for deciding if a result is an integer, and tells the user if it is.
+def is_result_integer(result)
+  if result == Integer(result)
+    puts "Your result is the integer, #{Integer(result)}"
+  end
+end
+
+puts "Hello, I am your calculator. As with most caluclators you have probably used, you will enter the first number in your calculation, then the operation, then the second number, and I will magically give you the result.
+Please enter your first number:"
+num_1 = gets.chomp
+
+# checks whether the user input is a number, and continues asking for input until a number is given
+until number_test(num_1)
+  puts "That is not a number. Please try again:"
+  num_1 = gets.chomp
+end
+num_1 = num_1.to_f
+
+
+puts "What operation shall we do?
+Choices: add (or +), subtract (or -), multiply (or *), divide (or /), exponentiate (or ^)"
+operation = gets.chomp
+
+#checks whether the user input is a valid operation, and continues asking for input until a valid response is given
+until ["add", "+", "subtract", "-", "multiply", "*", "divide", "/", "exponentiate", "^"].include? (operation)
+
+  puts "That wasn't one of the choices. Try again:"
+  operation = gets.chomp
+end
+
+
+puts "Please enter your second number:"
+num_2 = gets.chomp
+
+#checks whether the user input is a number, and continues asking for input until a number is given
+until number_test(num_2)
+  puts "That is not a number. Please try again:"
+  num_2 = gets.chomp
+end
+num_2 = num_2.to_f
+
+
+#methods to perform the calculating operations
+def add(num_1, num_2)
+  return num_1 + num_2
+end
+
+def subtract(num_1, num_2)
+  return num_1 - num_2
+end
+
+def multiply(num_1, num_2)
+  return num_1 * num_2
+end
+
+def divide(num_1, num_2)
+  return num_1 / num_2
+end
+
+def exponentiate(num_1, num_2)
+  return num_1 ** num_2
+end
+
+#Performs the requested calculation and displays results to the user. Also tells the user if the result is an integer. Gives an "impossible" message if the user tries to divide by zero.
+
+case operation
+when "add", "+"
+  sum = add(num_1, num_2)
+  puts "#{num_1} + #{num_2} = #{sum}"
+  is_result_integer(sum)
+when "subtract", "-"
+  difference = subtract(num_1, num_2)
+  puts "#{num_1} - #{num_2} = #{difference}"
+  is_result_integer(difference)
+when "multiply", "*"
+  product = multiply(num_1, num_2)
+  puts "#{num_1} * #{num_2} = #{product}"
+  is_result_integer(product)
+when "divide", "/"
+  if num_2 == 0
+    puts "C'mon, you know better than trying to divide by zero.\nCome back later when you've come to your senses!"
+  else
+    quotient = divide(num_1, num_2)
+    puts "#{num_1} / #{num_2} = #{quotient}"
+    is_result_integer(quotient)
+  end
+when "exponentiate", "^"
+  exponentiation = exponentiate(num_1, num_2)
+  puts "#{num_1} ^ #{num_2} = #{exponentiation}"
+  is_result_integer(exponentiation)
+end