Jacva BASICS (II) and jacva Basics

Jacva BASICS (II) and jacva Basics

Data Type Variable Operator

1. Data Type

Basic Type: Class 8

Integer: byte short int long

Floating Point (decimal): double float

Character: char

Boolean: boolean

Reference Type: String type

2. Variables

Essence: a space in the memory used to store various types of data.

Three elements: data type variable name variable value

Syntax for declaring variables:

I: name of the data type variable;

Variable name = variable value;

Ii: data type variable name = variable value;

3. Data Type Conversion

Automatic type conversion:

I: must be compatible with each other.

Ii: If the variable type is small, it can be automatically converted to a type with a large variable type. /* When either of the two numeric types is double

The result is automatically upgraded to the double type. */

4. Scanners

Import package:

Because the scanner class is in the java util package

Import java. util. vendor; // import the util package where the Scanner class is located

Wrote input = new partition (System. in );

System. out. print ("remind yourself of the type of data you want to enter ");

Char num1 = input. next (). charAt (0); // the first character of the char-type syntax input

5. Operators

I. Arithmetic Operators

+-*/%

Ii. Relational operators

><>==! =

Iii. assignment operator

= + =-=/= % =

Iv. logical operators

& Short circuit and | short circuit or & single and | single or! Non

V. Single Object Operator

Num ++ auto plus: num ++ = num + 1 num -- Auto minus: num -- = num-1

++ Executes the operation before the operation, and ++ performs the operation before the operation. -- Likewise