Java Job's hands-on brain

1 . Enum type is a reference type, but the output of an example does not refer to the same type. Enumeration types can have their own properties (parameters) and methods, and enumeration types can exist as separate files.

2, the first "x+y=" +x+y run result is the default is to add a character and a character, the second x+y+ "=x+y" Run result is the default first plus the number plus characters.

3, the value of the binary representation:

The original code: is the binary fixed-point notation, that is, the highest bit is the sign bit, "0" is positive, "1" is negative, the remaining bits represent the size of the value.

Inverse code:: The inverse code of positive number is the same as its original code; the inverse code of negative number is the inverse of its original code, except the sign bit.

Complement: The complement of a positive number is the same as its original code; the complement of a negative number is the minus 1 of its inverse code.

For Java, positive numbers are used for the original code. Inverse code for negative numbers.

4, the scope of the variable.

is the range of code that you can use to define variables.
Global variables: Variables that are defined in a class (not in a method) are available in this class.
Local variables: Variables defined in a method that, once out of this method, cannot be used.

Other:
There are also static variables that can be used directly with the class name.
Ordinary class variables are called with the class object.
The final variable cannot be changed after the assignment.

Java Job's hands-on brain