Java Core Technology Learning note the three programming structure

A basic data structure

Must be included in the class

Must have public static Main method

Case sensitive

Ii. Types of data

Four types of integers:

INT 4 byte short 2 byte Long8 byte byte1 byte

Two floating-point types

Float 4 bytes

Douleble 8 bytes

Char Type, Boolean type

Constants use the final definition class constants using the static final definition

Third, Operation symbols

X!=0 &&1/x>x+y//If x=0, do not perform the calculation behind && avoid x=0 1/x operation

Mathematical operation symbol MATH.PI, etc.

Iv. Conversion between values *

float f=9.98f;

int i= (int) F; I=9

int i= (int) math.round (f);//i=10

String comparison using equals

First, the data read into

Scanner in = new Scanner (system.in);

String name = In.nextline ();

int age = In.nextint ();

Java Core Technology Learning note the three programming structure