One of the ways A Clockwork Orange differs in movie and book form is the way which each is structured. In Burgess' novel, A Clockwork Orange is structured in a way that the very novel itself. The book is divided into 3 distinct sections, with periods of time going undescribed between each. One of the way's Kubrick's films is different is in how the film deals with these periods of time. For example, one of the times Kubrick actually adds information is immediately after Alex is sent to prison. Kubrick adds a scene which bridges these previously separate parts of the narrative.
It is interesting to note that this scene is nowhere to be found in the novel. While it may seem that the addition of this scene is merely a means of creating continuity in the film. It fundamentally alters the 3 staged structure that exists in the novel.
This continues in how Kubrick changes how the story ends. As with the American editions of the novel, the intended ending of A Clockwork Orange is entirely absent in the film. Kubrick instead chose to end his film with a rather dramatic and intense conclusion that changes how the story is interpreted.
.Burgess' book ends in a completely different way, instead leaving the reader to question whether Alex has or ever will mature, Burgess writes a third section that changes the way the reader interpret the book's theme