Shaunna Wiens --Carets

calculator2.rb

@@ -0,0 +1,141 @@
+#Define mathematical methods
+def add(a, b)
+  return a + b
+end
+
+def subtract(a, b)
+  return a - b
+end
+
+def multiply(a, b)
+  return a * b
+end
+
+def divide(a, b)
+  return a / b.to_f
+end
+
+def power(a, b)
+  return a ** b.to_f
+end
+
+def modulus(a, b)
+  return a % b
+end
+
+#Verify that entry is a number
+def verify_number(number, which)
+  until number.to_f.to_s == number || number.to_i.to_s == number
+    print "Please enter a numerical value for your #{which} number: "
+    number = gets.chomp
+  end
+  return number.to_f
+end
+
+#Determine whether to print a float or integer to the screen based on if it ends in zero (int)
+def float_or_int(number)
+  if number.to_s[-1] == "0"
+    number = number.to_i
+  end
+  return number
+end
+
+#Wasn't used.... this is a work in progress....Will use gsub to replace the parenthesis with the number.
+def parenth(number)
+  if number.to_s[0] == "(" && number.to_s[-1] == ")"
+    parenth_computation = number[1..(number.length)]
+    find_numbers(parenth_computation)
+    number = calculate(num1, operation, num2)
+  else
+    number = number
+  end
+  return number
+end
+
+#Calculates based on operation (Still need to delete extra words since they are replaced in line 108
+def calculate(num1, operation, num2)
+  case operation
+  when "+", "add", "plus"
+    operation = "+"
+    result = add(num1, num2)
+  when "-", "subtract", "minus"
+    operation = "-"
+    result = subtract(num1, num2)
+  when "/", "divide"
+    operation = "/"
+    if num2 == 0
+      result = "Error. Cannot divide by zero."
+    else
+      result = divide(num1,num2)
+    end
+  when "*", "x", "multiply", "times"
+    operation = "*"
+    result = multiply(num1, num2)
+  when "power", "exponent", "^"
+    operation = "^"
+    result = power(num1, num2)
+  when "modulus", "remainder", "%"
+    operation = "%"
+    result = modulus(num1, num2)
+  else
+    result = "42. Really, this isn't possible. But since 42 is the answer to life, the universe, and everything, we'll just assume it is also the answer to this operation that you've asked."
+  end
+end
+
+#Prompt user to enter math expression
+puts "Enter your mathematical expression using no spaces: "
+computation = gets.chomp
+
+#Prompts user to enter a valid math expression if they don't include an operator.
+while math_hash.to_a.flatten & computation.split("") == []
+  puts "Please enter a VALID mathematical expression"
+  computation = gets.chomp
+end
+
+#A hash that uses words as keys and the math symbols as values so that words can be replaced by symbols.
+math_hash = {
+  "plus" => "+",
+  "add" => "+",
+  "subtract" => "-",
+  "minus" => "-",
+  "multiply" => "*",
+  "times" => "*",
+  "x" => "*",
+  "divide" => "/",
+  "power" => "^",
+  "exponent" => "^",
+  "modulus" => "%",
+  "remainder" => "%"
+}
+
+#Replace math words with math symbols
+math_hash.each do |key, value|
+  computation.gsub!(key, value)
+end
+
+#Look for the index of the operator
+math_regex = /-|\*|\+|\^|\*|\/|%/
+operation_index = computation =~ math_regex
+
+#Determine the first number, operation, and second number
+num1 = computation[0...operation_index]
+num1 = verify_number(num1, "first")
+operation = computation[operation_index]
+num2 = computation[operation_index+1..-1]
+num2 = verify_number(num2, "second")
+
+#Calculate result
+result = calculate(num1, operation, num2)
+
+#Determine if numbers should be printed as floats or integers.
+num1 = float_or_int(num1)
+num2 = float_or_int(num2)
+result = float_or_int(result)
+
+#Prints equation and result to the sceen. If the power symbol is used, the resulting printout also shows the supporting multiplication.
+print "#{num1}#{operation}#{num2} = "
+if operation == "^"
+  print "#{num1}*" *(num2-1)
+  print "#{num1} = "
+end
+puts "#{result}"