A computer is a general-purpose electronic device that can be programmed to carry out a set of arithmetic or logical operations automatically. Since a sequence of operations can be readily changed, the computer can solve more than one kind of problem.
Conventionally, a computer consists of at least one processing element, typically a central processing unit (CPU), and some form of memory . The processing element carries out arithmetic and logic operations, and a sequencing and control unit can change the order of operations in response to stored information . Peripheral devices allow information to be retrieved from an external source, and the result of operations saved and retrieved.