The compiler system of the member variables of the class will automatically give the initial value, but it must be defined before it can be used, and initialization is not needed!

The default value of the member data type of this class is:

Boolean value: false

Bytes: 0

Short: 0

char:“\ u 0000”

Integer: 0

Floating: 0.0F

Double precision: 0.0

Object: empty

Local variables must be defined before they can be used, and they must be initialized, otherwise an error will be reported!