tags = [ "A", "IMG", "PRE" ]
tags.each{|tagname|
  case tagname
  when "P","A","I","B","BLOCKQUOTE"
    print tagname, " has child.\n"
  when "IMG", "BR"
    print tagname, " has no child.\n"
  else
    print tagname, " cannot be used.\n"
  end
}