how to enter an input to gets function via script in ruby

Whenever gets is called, is there any way to enter input via script itself, instead of entering manually in windows?

For examp开发者_如何学Gole:

puts "enter your choice"
ch=gets                           
puts ch

In the above script when gets is called, is there any command to enter input to that via a script in windows?

Thanks in advance.

The gets function simply reads from $stdin so all you have to do is open a new File or StringIO for reading and then assign it to $stdin.

For example, if you have a file called pancakes.txt and you do this:

$stdin = File.new('pancakes.txt', 'r')
puts gets

Then you'll see the first line of pancakes.txt on the standard output.

1) If you want to provide external input to STDIN when invoking your script

Let's say your gets command is inside a file named prog.rb. If you'd like to provide some fixed input to STDIN when running prog.rb, you could run it using a pipe from the command line:

echo "My input to gets" | ruby prog.rb

This will output

enter your choice
My input to gets

in the shell without requiring manual intervention.

2) An example for feeding STDIN from within the same script:

class MyIO
  def gets
    "1\n"
  end
end

$stdin = MyIO.new
puts "enter your choice"
ch=gets                           
puts ch # => 1