class String
def capitalize_first_letter
self[0].chr.capitalize + self[1, size]
end
def capitalize_first_letter!
unless self[0] == (c = self[0,1].upcase[0])
self[0] = c
self
end
end
end
s = 'this is a test'
puts s
puts s.capitalize_first_letter
puts s
puts s.capitalize_first_letter!
puts s