Time - Nataliya

calculator.rb

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+# 2/4/2020
+# Ada Classwork by Nataliya Pogodina
+
+def print_operation_instructions
+  puts "Welcome to Awesome Ruby Calculator"
+  puts "=================================="
+  puts "Please, choose a math operation:"
+  puts "1. add(+)"
+  puts "2. substract(-)"
+  puts "3. multiply(*)"
+  puts "4. divide(/)"
+  puts "(type a name or a symbol)"
+end
+
+def get_math_operation
+  operation_types = ["add", "+", "substract", "-", "multiply", "*", "divide", "/"]
+  math_operation = gets.chomp.downcase
+
+  until operation_types.include?(math_operation)
+    puts "Please, enter a valid operation!"
+    puts "(review the guide above!)"
+    math_operation = gets.chomp
+  end
+  return math_operation
+end
+
+
+def validate(input)
+  while input !~ /\A[+-]?\d+(\.\d+)?\z/ # regex
+    print "Please, enter a valid number: "
+    input = gets.chomp
+  end
+  return input.to_f
+end
+
+# Understanding the regex
+# /         start of the regex
+# \A        start of the string to be matched
+# [+-]?     zero or one of '+' or'-'
+# \d+       one or more of digit
+# (\.\d+)?  zero or one of 'one dot and 'one or more of digit'' 
+# \z        end of the string to be matched
+# /         end of the regex
+
+# def check_if_int(input)
+#   if input.to_s.include? "."
+#     display_number = input.to_f
+#   elsif
+#     display_number = input.to_i
+#   end
+#   return display_number
+# end
+
+def compute(math_operation, num1, num2)
+  case math_operation
+  when "add", "+"
+    result = num1 + num2
+  when "substract", "-"
+    result = num1 - num2
+  when "multiply", "*"
+    result = num1 * num2
+  when "divide", "/"
+    while num2 == 0
+      puts "\nYou can't devide by zero!"
+      print "Enter a different number: "
+      num2 = validate(gets.chomp)
+    end
+    result = num1 / num2
+  end
+  return result
+end
+
+def selector_symbol(math_operation)
+  case math_operation
+  when "add"
+    math_operation_display = "+"
+  when "substract"
+    math_operation_display = "-"
+  when "multiply"
+    math_operation_display = "*"
+  when "divide"
+    math_operation_display = "/"
+  else
+    math_operation_display = math_operation
+  end
+  return math_operation_display
+end
+
+def calculator 
+  print_operation_instructions
+  math_operation = get_math_operation
+
+  print "Please, enter the first number: "
+  num1 = validate(gets.chomp)
+
+  print "Please, enter the second number: "
+  num2 = validate(gets.chomp)
+
+  result = compute(math_operation, num1, num2)
+
+  math_operation_display = selector_symbol(math_operation)
+  puts "\nHere you go!"
+  puts "#{num1} #{math_operation_display} #{num2} = #{result}"
+end
+
+calculator