Primitive Types

These are the possible representations of data at any given address.

Somewhat depends on the language, but this is the list Wikipedia uses.

Boolean

True or false.

Character

Represents a symbol, usually in ASCII.

Interchangeable with integer in some languages.

Floating-Point Numbers

E.G. float, double.

Fixed-Point Numbers

E.G. decimal.

Integer

Integral or fixed-precision values.

Reference

A.K.A. pointer or handle.

Enumerated Type

A small set of uniquely named values.