I am trying to build a simple calculator with Ruby. Using Ruby Basic topics. Please help...

Question

Here is my code:

# This method greets the user on start up and request their name
# It returns their name
def greeting

  name = gets "Hello!  Please type your name: "

  puts "It is nice to meet you #{name}.  I am a simple calculator application.  \n
  I can add, subtract, multiply, and divide.\n"

  return name

end

# This method ask the user what type of calculation they would like to perform
# It returns the operation or an error for erroneous entry
def request_calculation_type

  operation_selection = gets "Type 1 to add, 2 to subtract, 3 to multiply, or 4 to divide two numbers: "

  if operation_selection == 1 
    return "add"
  elsif operation_selection == 2
    return "subtract"
  elsif operation_selection == 3
    return "multiply"
  elsif operation_selection == 4
    return "divide"
  else return "error"

end

# This method performs the requested calculation
# It returns the result of the calculation
def calculate_answer(operator, a, b)

  if operator == "add"
    return result= a + b
  elsif operator == "subtract"
    return result = a - b
  elsif operator == "multiply"
    return result = a * b
  elsif operator == "divide"
    return result = a / b

end

name = greeting
run_calculator = 1

while run_calculator == 1

  current_calculation = request_calculation_type()

  if current_calculation == "error"

    puts "I do not understand this type of calculation... Can we try again?"  

  else

    first_number = gets "What is the first number you would you like to #{calc_type}: "
    second_numer = gets "What is the second number you would like to #{calc_type}: "

    answer = calculate_answer(current_calculation, first_number, second_number)

    puts "The answer is #{answer}"
    run_calculator = gets "Type 1 to run another calcution or 2 to end: "

  end
end

Here is the error:

calculator.rb:69: syntax error, unexpected end-of-input, expecting keyword_end

FYI - Line 69 is the end in the code

Please help... I would like to accomplish this as my first Ruby program ;-)

Answer 1 · 2014-08-18T17:31:49Z

August 18, 2014 5:31pm

I had a play and had more success with this:

# This method greets the user on start up and request their name
# It returns their name
def greeting
  puts "Hello!  Please type your name: "
  name = gets
  puts "It is nice to meet you #{name}.  I am a simple calculator application.  \n
  I can add, subtract, multiply, and divide.\n"
  name
end

# This method ask the user what type of calculation they would like to perform
# It returns the operation or an error for erroneous entry
def request_calculation_type
  puts "Type 1 to add, 2 to subtract, 3 to multiply, or 4 to divide two numbers: "
  operation_selection = gets.to_i

  if operation_selection == 1 
    "add"
  elsif operation_selection == 2
    "subtract"
  elsif operation_selection == 3
    "multiply"
  elsif operation_selection == 4
    "divide"
  else 
    "error"
  end

end

# This method performs the requested calculation
# It returns the result of the calculation
def calculate_answer(operator, a, b)
  if operator == "add"
    a + b
  elsif operator == "subtract"
   a - b
  elsif operator == "multiply"
    a * b
  elsif operator == "divide"
    a / b
  end
end

name = greeting
run_calculator = 1

while run_calculator == 1

  current_calculation = request_calculation_type()

  if current_calculation == "error"

    puts "I do not understand this type of calculation... Can we try again?"  

  else
    puts "What is the first number you would you like to #{current_calculation}: "
    first_number = gets.to_i
    puts "What is the second number you would like to #{current_calculation}: "
    second_number = gets.to_i 

    answer = calculate_answer(current_calculation, first_number, second_number)

    puts "The answer is #{answer}"
    puts "Type 1 to run another calcution or 2 to end: "
    run_calculator = gets.to_i

  end
end

Answer 2 · 2014-08-18T16:57:03Z

August 18, 2014 4:57pm

Are you missing an end statement for either of the if statements in "def calculate_answer(operator, a, b)" and "def request_calculation_type"?

def calculate_answer(operator, a, b)

  if operator == "add"
    return result= a + b
  elsif operator == "subtract"
    return result = a - b
  elsif operator == "multiply"
    return result = a * b
  elsif operator == "divide"
    return result = a / b
#missing end?

end

Answer 3 · 2014-08-18T17:49:15Z

August 18, 2014 5:49pm

Yeah that was it! gets.to_i

Thanks Tom!!!

Here is the edited code:

# This method greets the user on start up and request their name
# It returns their name

def greeting

  puts "Hello!  Please type your name: "
  name = gets
  puts "It is nice to meet you #{name}"  
  puts "I am a simple calculator application.  I can add, subtract, multiply, and divide."

  return name

end

# This method ask the user what type of calculation they would like to perform
# It returns the operation or an error for erroneous entry
def request_calculation_type

  puts "Type 1 to add, 2 to subtract, 3 to multiply, or 4 to divide two numbers: "
  operation_selection = gets.to_i

  if operation_selection == 1 
    return "add"
  elsif operation_selection == 2
    return "subtract"
  elsif operation_selection == 3
    return "multiply"
  elsif operation_selection == 4
    return "divide"
  else 
    return "error"

  end

end

# This method performs the requested calculation
# It returns the result of the calculation
def calculate_answer(operator, a, b)

  if operator == "add"
    return result= a + b
  elsif operator == "subtract"
    return result = a - b
  elsif operator == "multiply"
    return result = a * b
  elsif operator == "divide"
    return result = a / b
  end

end

name = greeting
run_calculator = 1

while run_calculator == 1

  current_calculation = request_calculation_type()

  if current_calculation == "error"

    puts "I do not understand this type of calculation... Can we try again?"  

  else
    puts "What is the first number you would you like to #{current_calculation}: "
    first_number = gets.to_i
    puts "What is the second number you would like to #{current_calculation}: "
    second_number = gets.to_i

    answer = calculate_answer(current_calculation, first_number, second_number)

    puts "The answer is #{answer}"
    puts "Type 1 to run another calculation or 2 to end: "
    run_calculator = gets.to_i

    if run_calculator != 1

      puts "Thanks for working with me to crunch some numbers!  See you later ;-)"

    end
  end
end

Answer 4 · 2014-08-18T16:59:02Z

August 18, 2014 4:59pm

Have you looked at both "def calculate_answer(operator, a, b)" and "def request_calculation_type"? *

Answer 5 · 2014-08-18T17:01:11Z

August 18, 2014 5:01pm

Thanks Tom! That resolved the error.

However, the calculator is not working. None of the puts statements seem to output.

Am I calling the methods incorrectly?

Answer 6 · 2014-08-18T17:13:08Z

August 18, 2014 5:13pm

Your "gets" Syntax needs to be more like: (or atleast - this worked for me)

puts "What is your name: "
name = gets

Answer 7 · 2014-08-18T18:04:09Z

August 18, 2014 6:04pm

i would like to see this app when it is done.

Answer 8 · 2014-08-18T18:07:41Z

August 18, 2014 6:07pm

You can add the code in my last comment to a new Workspace. Nothing fancy... It's ALIVE!!!

Answer 9 · 2014-08-18T18:18:00Z

August 18, 2014 6:18pm

Here is a better version with formatting that makes the program easier to read:

# This method greets the user on start up and request their name
# It returns their name

def greeting

  puts "Hello!  Please type your name: "
  name = gets
  puts "\n" + "It is nice to meet you #{name}"  
  puts "\n" + "I am a simple calculator application.  I can add, subtract, multiply, and divide."

  return name

end

# This method ask the user what type of calculation they would like to perform
# It returns the operation or an error for erroneous entry
def request_calculation_type

  puts "\n" + "Type 1 to add, 2 to subtract, 3 to multiply, or 4 to divide two numbers: "
  operation_selection = gets.to_i

  if operation_selection == 1 
    return "add"
  elsif operation_selection == 2
    return "subtract"
  elsif operation_selection == 3
    return "multiply"
  elsif operation_selection == 4
    return "divide"
  else 
    return "error"

  end

end

# This method performs the requested calculation
# It returns the result of the calculation
def calculate_answer(operator, a, b)

  if operator == "add"
    return  a + b
  elsif operator == "subtract"
    return  a - b
  elsif operator == "multiply"
    return a * b
  elsif operator == "divide"
    return a / b
  end

end

name = greeting
run_calculator = 1

while run_calculator == 1

  current_calculation = request_calculation_type()

  if current_calculation == "error"

    puts "\n" + "I do not understand this type of calculation... Can we try again?"  

  else
    puts "\n" + "What is the first number you would you like to #{current_calculation}: "
    first_number = gets.to_i
    puts "\n" + "What is the second number you would like to #{current_calculation}: "
    second_number = gets.to_i

    answer = calculate_answer(current_calculation, first_number, second_number)

    puts "\n" + "The answer is #{answer}"
    puts "\n" + "Type 1 to run another calculation or anything else to end: "
    run_calculator = gets.to_i

    if run_calculator != 1

      puts "\n" + "Thanks for working with me to crunch some numbers!  See you later ;-)"

    end
  end
end

Answer 10 · 2017-03-24T12:24:12Z

March 24, 2017 12:24pm

just tried this ! is amazing ! thank you

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