-- print3.hs

module Print3 where

  myGreeting :: String
  myGreeting = "hello" ++ " world!"

  hello :: String
  hello = "hello"

  world :: String
  world = "world!"

  main :: IO ()
  main = do
    putStrLn myGreeting
    putStrLn secondGreeting where 
      secondGreeting = concat[hello, " ", world]


  --area d = pi * (r * r)
  --r = d / 2

  area d = pi * (r * r) where
    r = d / 2