JAVA program, basic data type, data type conversion, variables and constants, common operators, java Operators

JAVA program, basic data type, data type conversion, variables and constants, common operators, java Operators

I. Basic Data Types

Integer type: byte, short, int (commonly used), long (usually used)

Defines a variable int a = 10;

 

Floating point type (decimal): float, double (commonly used)

 

Character Type: char (not a string)

Char B = 'A'

Escape Character class: Common \ backslash character \ t vertical tab \ r carriage return \ n line feed

　

Boolean (logical type): true, false

 

Ii. type conversion

Forced conversion and automatic conversion

Int m = 1;

Long n = 4;

N = m; short values can be automatically assigned to long values.

M = n requires us to forcibly convert the Syntax: m = (int) n

The forced conversion between values is implemented ().

 

3. Variables and constants

Variable: int a, B; double c = 3.14;

Constant final: values can only be assigned once. All objects share values. final double d = 3.1415;

 

Iv. Common Operators

Arithmetic Operators: +,-, *,/, %, ++, and ,--

Relational operators: >>=<==! =

Logical OPERATOR: & |!

Other operators: + =-= * =/= % =? : =