Ruby: Prompting for multiple inputs

Question

I'm trying to get multiple inputs and assign it to different variables (in the irb) but I can't seem to get it to work. I'm only able to do it for the first variable, but for the next three, the last input gets assigned to the other 2 (I have 4 in all)

What I'm trying to do is, based on the first input (say, 2), it'll prompt for 3 more inputs 2 times.

t = gets.to_i

This is the first input and it gets assigned properly. It'll then prompt for 3 more inputs, but then only the last input gets saved and is assigned to all three variables.

a = gets.to_i
b = gets.to_i
k = gets.to_i

it'll accept 3 inputs but only the last gets saved?

say if I enter (for the first iteration)

1
10
3

after the first prompt (which i entered 2) a, b, and k has value 3

t = gets.to_i
a = b = k = []

for i in 0..t-1 do
  a[i] = gets.to_i
  b[i] = gets.to_i
  k[i] = gets.to_i
end

Is it because it's in a loop? I'm putting it there since it has to ask for the values of a, b and k for t times where t is the first input.

I'm not sure if I explained it properly but I hope someone can understand what I was trying to do

Hint: how many arrays do you create in your code? There are two ways to create an array, using an array literal (e.g. []) or by calling one of the Array factory methods (e.g. Array::[] or Array::new). Count the number of calls to factory methods and count the number of array literals in your code. — Jörg W Mittag
– Jörg W Mittag, Commented Mar 26, 2017 at 12:15
@JörgWMittag I see it now. Thank you!! (esp for not answering it explicitly) :) I appreciated it. — kimsanity
– kimsanity, Commented Mar 26, 2017 at 23:14

Aleksei Matiushkin · Accepted Answer · 2017-03-26 07:10:48Z

2

The only way to address a variable in Ruby is by reference. That said,

a = b = k = []

declares three references to the same object. To fix it, declare arrays separately:

t = gets.to_i
a, b, k = [], [], []

for i in 0..t-1 do
  a[i] = gets.to_i
  b[i] = gets.to_i
  k[i] = gets.to_i
end

Sidenote: for loop is not ruby idiomatic. Use e. g. Range#each instead (or Integer#upto):

(0...t).each do |i| # or 0.upto(t - 1) do |i|
  a[i] = gets.to_i
  b[i] = gets.to_i
  k[i] = gets.to_i
end

edited Mar 26, 2017 at 7:10

answered Mar 26, 2017 at 7:03

Aleksei Matiushkin

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