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Jeff Lange
8,788 PointsHow do you call a method from inside another method? Should I be using some sort of loop?
I'm a ruby newb, and I like to invent simple, personal challenge programs for myself. Today my task was to create a program that would add two numbers inputted by the user.
I got the basic program to work fine. The issue I'm having is that I want to give the user the choice of having the program restart. Unlike in javascript, it appears I can't call a method ("function" in javascript terms) from within another method. The code below yields the error:
"rb:29:in 'again': undefined local variable or method 'add_num' for [object ID] NameError)."
I've tried getting for and while loops to work, but I'm obviously not grasping something enough to make it happen. Here's the code:
class Adder
def initialize ()
end
def add
puts "This app will add two numbers together for you! Please select your first number. "
x = gets.to_f
puts "Excellent! Please select your second number. "
y = gets.to_f
puts "The sum of your numbers is #{x + y}. "
end
def again
puts "Would you like to add again? (y/n)"
response = gets.chomp
if response == "y"
add_num.add
else
puts "Goodbye!"
end
end
end
add_num = Adder.new()
add_num.class # => Adder
add_num.add
add_num.again
I have the feeling this is supremely simple and I'm just missing it or haven't quite been taught it yet. Any thoughts? Thanks!
2 Answers
Joseph Kato
35,340 PointsYour issue seems to be that you're attempting to reference add_num from within the class itself, even though add_num was defined outside of the class definition.
There are many options to fix this issue, but one simple way would be to change (from within the again method):
add_num.add
To just:
add
Ricky Catron
13,023 PointsYou could do something like make a while loop and while input not equal to quit run the program else quit the program.
Jeff Lange
8,788 PointsCan you show me a quick example of how I would do that? I tried creating a while loop like this:
def add
while response == "y"
[code]
end
but I got the same error of the variable "response" being undefined, which confused me since, well, near as I can tell I did define it.
Ricky Catron
13,023 PointsI don't know Ruby sorry. A basic example would be
response = y
while response == y
[code]
[input new variable for response if you want to keep going]
end
Jeff Lange
8,788 PointsJeff Lange
8,788 Pointsahhh!!! You're so right! For some reason I was trying to call the method as if I was outside the class even though i was within it.
In the "again" method I changed it to
addand in the add method I inserted a call to the again method by just puttingagain. Now it works exactly like I wanted it to: every single time it adds the numbers it asks if you want to add anymore (y/n), and loops if you type y, and ends if you type n. Awesome!Thank you Joseph! Super helpful! As simple as that was, that should actually solve a lot of issues I've been running into the past few days. You helped me break through a mental barrier.