Answer:The full form of CUI is Character User Interface. The full form of GUI is Graphical User Interface.
Character User Interface refers to that interface in which the user himself interacts with the computer with the help of the keyboard and he needs a command so that he can carry on doing a particular job.
Graphical User Interface refers to that interface which helps the users in interacting with the application or the operating system. It reduces the burden from CPU and performs some of the functions very quickly.