Program to find smallest and longest substring of a string in Ruby

Write a program to find smallest and longest substring of a string in Ruby

class FindSmallestAndLongestSubstring
  def findSmallestAndLongestSubstring
    print "Enter the string: "
    input_string = gets.chomp
    all_substrings = input_string.split(" ")
    smallest_string = all_substrings[0]
    longest_string = all_substrings[0]
    all_substrings.each do |s|
      smallest_string = s if smallest_string.length > s.length
      longest_string = s if longest_string.length < s.length
    end 
    puts "Smallest substring: #{smallest_string}"
    puts "Longest substring: #{longest_string}"
  end
end

p = FindSmallestAndLongestSubstring.new 
p.findSmallestAndLongestSubstring

Output:

Enter the string:  umesh kushwaha best ror developer
Smallest substring: ror
Longest substring: developer