: Similar to most languages, you can define names to be used in your
code. Enum labels must all start with an uppercase letter.
- Struct: Structures contain members. A struct value contains the first member and the second member and the third member, and so on. Structure member names begin with a lowercase letter.
- Tagged Union: Tagged unions also contain members. A tagged union value contains the first member or the second member or the third member, and so on. Tagged union member names begin with a lowercase letter.
Defining Typestypedef is used to define a type synonym and the user defined types Enum, Struct, and Tagged Union.