How to write negative loop in ruby like for(i=index; i >= 0; i –)

There are many ways to perform a decrementing loop in Ruby:

First way:

for i in (10).downto(0)
  puts i
end

Second way:

(10).downto(0) do |i|
  puts i
end

Third way:

i=10;
until i<0
  puts i
  i-=1
end