C + + Learning notes-literal constants class

Literal constant class: An aggregate class in which data members are literal types is a literal constant class. If a class is not an aggregation class, but it meets the requirements, it is also a literal constant class:

1. Data members must be of literal type.

2. A class must contain at least one constexpr constructor.

3. If a data member contains an initial value within the class, the initial value of the built-in type member must be a constant expression, or if the member belongs to a type, the initial value must use the member's own constexpr constructor.

Constexpr constructor:

1, although the constructor cannot be const, the constructor of a literal const class can be a constexpr function. In fact, a literal constant class must provide at least one constexpr constructor.

C + + Learning notes-literal constants class