Who played Arthur Fleck in 'Joker'?

Who played John Nash in 'A Beautiful Mind'? Who played Max Rockatansky in 'Mad Max: Fury Road'? Who played Imperator Furiosa in 'Mad Max: Fury Road'? Who played Bane in 'The Dark Knight Rises'? Who played Bruce Wayne in 'Batman Begins'? In which film is Bruce Wayne a character? In which film is Tony Stark a character? Who played Steve Rogers in 'Captain America: The First Avenger'?