In C++, a structure is a construct used to group variables of different data types under a single name, while a class is a more comprehensive construct that includes both data members and member functions. Structures are often used for simple data organization, while classes provide the foundation for object-oriented programming with encapsulation and inheritance.
Another distinction is that structure members are public by default, allowing direct access, whereas class members are private by default, requiring access through public member functions.
Additionally, classes support inheritance, while structures do not. The choice between structure and class depends on the complexity and requirements of the program or system being developed.