A simple ruby script to Write n number of Odd or Even numbers into file.

EVEN_and_ODD.rb

puts "Enter 0 for even and 1 for Odd."
inp = gets.to_i

case inp
  
 when 0
   
    file = File.open("file_writer.txt",'w')
    for i in 1..1000 do                             # Specify the range for EVEN loop
      file.write(i, ' ') if i.even?
    end
    sleep 0.5
    puts "EVEN numbers written into the file!!!"
    puts 'closing file...'
    sleep 1
    puts "file closed"
    file.close

 when 1
      
   file = File.open("file_writer.txt",'w')
   for i in 1..1000 do                              # Specify the range for ODD loop
     file.write(i, ' ') if !i.even?
   end
   sleep 0.5
   puts "ODD numbers written into the file!!!"
   puts 'closing file...'
   sleep 1
   puts "file closed"
   file.close
   
 else
   puts "Please enter valid digit!!, try again"
   
end

=begin
 HOW TO RUN:
1. Open terminal
2. type: ruby FILENAME

=end