Who played Doc Brown in 'Back to the Future'?

Who played Rose in 'Titanic' (1997)? Who played Maverick in 'Top Gun' (1986)? Who played Iceman in 'Top Gun' (1986)? Who played Marty McFly in 'Back to the Future'? Who played Ferris Bueller in 'Ferris Bueller's Day Off'? Who played Dorothy in 'The Wizard of Oz' (1939)? Who played Scarlett O'Hara in 'Gone with the Wind'? Who played Rick Blaine in 'Casablanca'?