The differences between a class and a struct in C++ is:

struct members and base classes/structs are public by default.
class members and base classes/struts are private by default.

Both classes and structs can have a mixture of public, protected and private members, can use inheritance and can have member functions.

I would recommend you:

use struct for plain-old-data structures without any class-like features;
use class when you make use of features such as private or

protected members, non-default constructors and operators, etc.