A scalar is a single unit of data. Scalar data types are single-valued data types, that can be used for individual variables, constants, etc.
Recall the elementary types that we saw earlier:
STRING is a bit of a hybrid. A string is made up of multiple characters, that can be manipulated individually. It still counts as a scalar type, though, since a string can be treated as a single data value.
Ada programmers are not limited to the above built-in types. You can define your own types. They can be structured types, which combine multiple data items into a larger unit, or they can be scalar (single-valued) types.
Scalar types can be:
Each distinct type needs its own I/O library.