Lets first understand the various classification of Data Types
1. Fundamental or Built-in data types (Primary Data Types).
2. Derived data types (Secondary Data Types).
3. User Defined data types.
The basic built-in or fundamental data types that are available in any programming language, in C we have int, float, double and char as builtin data types.
Derived data types are those data types which are derived from the fundamental data types using some declaration operators. In C we have Arrays, Functions and pointers, Structures and Classes as derived or secondary data types.
I hope this will clear your doubt.