The concept of C + + Primer notes 2

C++11 The new standard specifies that a data member can be provided with a class-within initial value. When an object is created, the initial value in the class is used to initialize the data member. With no initial value

The member will be initialized by default.

The restrictions on the initial values in the class are similar to those described earlier: either in curly braces or on the right side of the equals sign, remember not to use parentheses

Header files typically contain entities that can only be defined once, such as classes, const, and constpxpr variables.

Note: Once the header file is changed, the associated source file must be recompiled to obtain the updated declaration.

Types are divided into constants and extraordinary quantities, and a constant object must be initialized and cannot be changed once its value is initialized.

Default initialization initializes the initialization behavior that is performed by the class itself when the object is not shown to be given the initial value.

Initializes the behavior of the class object. The built-in type object of the global scope is initialized to 0: The local scope object is not initialized and has an undefined value.

Void* can point to any number of pointer types and cannot perform dereference operations

The void type is a type of special use that has no operation and no value. You cannot define a variable of type void.

The concept of C + + Primer notes 2