Breaking the loop in case of EOF

[Marcin Górski]

Hello,
I need to break a loop when program gets an EOF from STDIN. For example
in C++ I would do it by following way:

while(1) {
if((cin >> a).eof()) break;
}

I don't know how do it in Ruby. I tried the idea, but it doesn't work
well:
irb(main):007:0> loop do
irb(main):008:1* str = gets.chomp
irb(main):009:1> break if STDIN.eof?
irb(main):010:1> puts "String: " + str
irb(main):011:1> end
hey
joe
String: hey
hey
String: joe
hey
String: hey
=> nil

Thank you for your attention,

 

[Brian Candler]

I need to break a loop when program gets an EOF from STDIN.

gets will return nil in this case.

while str = STDIN.gets
str.chomp!
puts "String: #{str}"
end

Beware that "STDIN.gets" is subtly different from a bare "gets". The
first always reads from STDIN. The second will read from the files named
on the command line if the command line is not empty. (See also ARGF).

 

[Robert Klemme]

gets will return nil in this case.

while str =3D STDIN.gets
=A0str.chomp!
=A0puts "String: #{str}"
end

Beware that "STDIN.gets" is subtly different from a bare "gets". The
first always reads from STDIN. The second will read from the files named
on the command line if the command line is not empty. (See also ARGF).

I believe a more idiomatic way would be

STDIN.each do |str|
str.chomp!
puts "String: #{str}"
end

Kind regards

robert

--=20
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/

 

[Marcin Górski]

Thanks for your answers.

 

[Sebastian Hungerecker]

while str = STDIN.gets
str.chomp!
puts "String: #{str}"
end

Which can also be written as:
STDIN.each_line do |str|
...
end