Java Basic applications

symbols for bitwise operators:

& ( with ): Both are 1 When I am one, the others are 0

| ( or ) : Both are 0 only when the 0 , the others are 1.

^ ( xor ): The difference between the two is 1, the same as 0

~ ( inverse ):0 becomes 1,1 becomes 0.

the representation of negative numbers: The highest bit of bits is 1, so this number is a negative.

rule: Negative number corresponding to the positive number-1 , the inverse negative number corresponding to the positive number reversed +1

Role: Data is encrypted

shift Operators :

>> Right Shift

rule: shift the number of digits to the right by dividing by 2 How many times you want to move

<< left Shift

rule: how many digits to the left, multiply the number by 2 times.

>>> unsigned Right shift

function : increases the operation rate. Bit arithmetic is the fastest execution.

features : A number A and two the same number ^, the final result is still the original number a.

Looping Statements

While loop: First judge the execution

Structure:

while ( loop condition ) {

Loop body.

}

do and loop: once executed, the loop body is bound to execute once .

structure :

bo=

circulation body ;

}while ( cyclic conditions );

For Loop:

Structure:

for (;;) {

Loop body

}

Java Object-oriented programming:

The three main characteristics of object-oriented: encapsulation, inheritance, polymorphism. Class, Object.

Object: The only thing that really exists.

Object-oriented programming (OOP) idea: is to make the description of things in computer language and the things in nature as consistent as possible.

Object-oriented Core: Find the right object to do the right thing.

How to find the right object in Java:

1.sun classes are already assigned, and you need to know these classes to create objects from custom-made classes.

2. Customize the class to create the object from the custom class.

The class contains: properties, methods.

The definition format of the class:

Class name {

Attribute (member variable): Describes the public characteristics of a thing.

Method: Describe the behavior of a thing (what to do)
}

Create an object from a custom class

Format:
Class Name Object name (variable name) = new class name ();

Creating objects from the car class
Car car = new car ();

Setting properties
Car.color = "Red";
Car.name = "BMW";

Call Method:
Car.run ();

Java Basic applications