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I'm trying to define a method that countdowns 10 to 0 and at the end returns HAPPY NEW YEARS! however i don't want i"am doing wrong?
def countdown(number)
while number > 0
puts "#{number} SECONDS(S)!"
number -= 1
end
"HAPPY NEW YEAR!"
end
A quick Google search revealed that you are apparently trying to solve https://learn.co/lessons/countdown-to-midnight (you really should have included that link)
Your code is not passing the spec, because it contains an additional S:
puts "#{number} SECONDS(S)!"
# ^
It has to be:
puts "#{number} SECOND(S)!"
def countdown(number)
while number > 0
puts "#{number} SECONDS(S)!"
number -= 1
end
puts "HAPPY NEW YEAR!"
end
I added a puts on the last line of your code. You method is counting down to 0 seconds, but the last line only return the string "HAPPY NEW YEAR!", and does not print it to the screen. Or if you need to return the string and print it on the screen, you can do p "HAPPY NEW YEAR!"
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Code not returning the correct answer.
I've tired assigning a value to the animal choices. I've put it in the def and outside of it.
puts "Choose your favorite: cats or dogs"
choose = gets
cats = 1
dogs = 2
def favorite_animal (number)
remainder_when_divided_by_2 = number % 2
if remainder_when_divided_by_2 == 0
return "Ken does too."
end
if remainder_when_divided_by_2 == 1
return "Dogs are better!"
end
end
If the user enters Cats the answer "Ken does too!" should show. If the user enters Dogs the answer "Dogs are better!" should show. All I've gotten is 1 or 2 as an answer.
Try this.
loop do
puts "Choose your favorite: cats or dogs"
case gets.chomp
when "cats"
break "Ken does too."
when "dogs"
break "Dogs are better!"
else
puts "That answer is invalid. Try again"
end
end
Here is an example of a session using this code, with my answers being "pigs" and "dogs".
Choose your favorite: cats or dogs
pigs
That answer is invalid. Try again
Choose your favorite: cats or dogs
dogs
#=> "Dogs are better!"
See Kernel#loop. Many Rubyists use loop with the keyword break for most loops, rather than while or until. (for loops are never used).
For what you are doing you don't need a method, but if you want one add the line
def favorite_animal
at the beginning and the line
end
at the end. Then
favorite_animal
#=> "Dogs are better!"
provided I were to give the same answers as I did earlier.
There's a couple things going on:
You have to call the method favorite_animal somewhere; you've only defined it
Your cats/dogs isn't "mapped" to anything, so you need some logic to convert your input into a number, before you call the favorite_animal method
You still have to do something with the value you return inside your method (puts or something else to get it to show)
Here's a minimum example that works that might be useful for you to see the 3 issues above
def favorite_animal (number)
remainder_when_divided_by_2 = number % 2
if remainder_when_divided_by_2 == 0
return "Ken does too."
end
if remainder_when_divided_by_2 == 1
return "Dogs are better!"
end
end
puts "Choose your favorite: cats or dogs"
choose = gets.chomp
answer = if choose == 'cats'
1
else
2
end
puts favorite_animal(answer)
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I'm new to ruby, and I'm trying to make a simple calculator in which a user types in a simple problem (such as addition or subtraction) and the answer is returned. The problem is when the user types in a question, the question itself is being returned instead of the answer to that question.
puts "How many Questions?"
questions = gets.chomp.to_i
questions.times do |problem|
puts "question: "
problem = gets.chomp
puts "answer: #{problem}"
end
Inside your loop, instead of:
problem = gets.chomp
puts "answer: #{problem}"
Try this:
problem = gets.chomp
solved_problem = eval(problem)
puts "answer : #{solved_problem}"
eval will take care of interpreting your string as a Ruby instruction. But it's very messy, because anyone could write any Ruby program in your input and eval will make it run, so it's not safe at all.
If you only want to take care of simple operations, you can use a regex first to check if the input string looks like what you want:
problem_is_ok = (problem =~ /^\d+ *[+-] *\d+$/)
This will be true if the string starts with a number, followed by 0 to many spaces, followed by either a + or - sign, followed by 0 or more spaces, followed by another number and nothing else. Then you raise an error if this is not true.
Your loop now look like this:
questions.times do |problem|
puts "question: "
problem = gets.chomp
problem_is_ok = (problem =~ /^\d+ *[+-] *\d+$/)
if problem_is_ok
puts "answer: #{eval(problem)}"
else
#I raise an error, but you might aswell just print it instead for your simple program
raise ArgumentError("Can't compute this")
end
end
Add and subtract can be simple ruby definitions
We pass in 5 and 1
The lower portion of the code is the clear user interface implementation
when we loop we do it 3 times
It outputs 3 options for the user to select from
We read in with chomp, standard in, the keyboard, chooses 1, 2, or 3
If elsif statements conditionally select for each case
Using string interpolation we render the variables a and b into a new string,
and run their respective methods (add or subtract)
Converting that methods integer output to a string, and concatenate it.
Outputting that to the users screen
The 3rd option does no calculation,
instead it prints to users screen a simple string
our else condition catches the case when people don't enter one of the choices of 1, 2 or 3
It tells you to correct your choice to the options provided
Hope this helps
#!/usr/bin/env ruby
questions = 3
a, b = 5, 1
def add(a,b)
a + b
end
def subtract(a,b)
a - b
end
questions.times do |questions|
puts "Please choose:
1. add
2. subtract
3. exit"
questions = gets.chomp
if questions == '1'
puts "#{a} + #{b} = " + add(a,b).to_s
elsif questions == '2'
puts "#{a} - #{b} = " + subtract(a,b).to_s
elsif questions == '3'
puts 'exiting, goodbye.'
exit
else
p 'please choose again'
end
end
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I have two methods turn_count(board) and current_player(board). The turn_count(board) method, which returns the number of "X"s and "O"s in an array is working appropriately. But the current_player(board) method, which is supposed to puts "X" if turn_count(board) is even and "O" if turn_count(board) is odd keeps giving me an error. The error is:
/Users/john/Desktop/test file.rb:13:in current_player': undefined method%' for nil:NilClass (NoMethodError)
from /Users/john/Desktop/test file.rb:18:in `'
Clearly it's saying there's an issue with the modulo operator being used, but i'm not sure why and have been wracking my brain trying to figure it out.
Any help is greatly appreciated!
def turn_count(board)
count = 0
board.each do |x| if x == "X" || x == "O"
count = count + 1
end
end
puts count
end
def current_player(board)
if turn_count(board) % == 0
puts "X"
else
puts "O"
end
end
The problem is you are using % on a NilClass. Your turn_count() method returns nil. Check what happens if you replace puts count with count.
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Just started to go through the 7 languages in 7 weeks book; day one problem make a simple higher or lower game in ruby. When I execute my script I get the following error but I don't know why.
EDIT: This is thrown after I guess once.
NameError: undefined local variable or method actual' for main:Object
from guess_game.rb:2:inguess'
from guess_game.rb:22
def guess(guess, acutal)
unless guess == actual
if guess > actual
puts 'Lower'
else
puts 'Higher'
return false
end
end
puts 'Correct'
return true
end
answer = rand(10)
game_won = false
puts 'I am thinking of a number, what is it?'
until game_won
num = gets.to_i
# Static Debug Line
puts "Guess #{num} : Answer #{answer}"
game_won = guess(num, answer)
end
def guess(guess, actual)
unless guess == actual
if guess > actual
puts 'Lower'
else
puts 'Higher'
return false
end
end
puts 'Correct'
return true
end
Problem: Spelling mistake, Corrected
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I am trying to write a Ruby loop for the song "99 Bottles of Beer On The Wall" for an exercise from the book "Learn To Programs". What am I doing wrong? I have the following:
def bottles_of_beer
i = 99
while i < 99 and i > 0
puts "#{a} bottles of beer on the wall. #{a} bottle of beer."
i = i - 1
puts "Take one down, pass it around. #{i} bottle of beer on the wall."
end
end
You are referencing undefined variable a in your first string.
I have simplified your code by quite a bit:
i = 99
while i < 99 and (anything else)
(anything)
end
Try and see if you can figure it out now.
TL;DR
You have many problems with your code, not least of which i starts out equal to 99, so the rest of the code block is never evaluated. Even if you fix that, a will always be nil because you never assign anything to it.
Fix Your Conditional
There are many ways to do this, but you probably want to use the >= or <= methods for your comparisons.
Be More Idiomatic
Using Integer#downto and a block would be much more idiomatic. For example:
12.downto(1) { |count| p "#{count} bottles of beer on the wall..." }
p "You drank the whole case!"
Perhaps...
99.downto(1) do |i|
puts "#{i} bottle#{i==1 ? '' : 's'} of beer on the wall, #{i} bottle#{i==1 ? '' : 's'} of beer!"
puts "Take one down, pass it around, #{i-1} bottle#{i-1==1 ? '' : 's'} of beer on the wall!"
end
To give you a definitive answer, there are three reasons why your code produces no output
You set i to 99 and then loop while i < 99 and i > 0, so the loop is never executed. Since you are always decrementing i, there is no need for anything more than while i > 0
You interpolate the variable a into the string you are printing. Since you haven't declared it your program will refuse to run, saying undefined local variable or method 'a'
You never actually call your method.
Fixing these three problems gives this (non-idiomatic, but working) program
def bottles_of_beer
i = 99
while i > 0
puts "#{i} bottles of beer on the wall. #{i} bottle of beer."
i = i - 1
puts "Take one down, pass it around. #{i} bottle of beer on the wall."
end
end
bottles_of_beer