Java Learning notes: Variables for Java

First, Introduction

In the Java language, all variables must be declared before they are used. The basic format for declaring variables is as follows:

Type identifier [= value][, identifier [= value] ...];

Format Description: Type is a Java data type. Identifier is the variable name. You can declare multiple variables of the same type by separating them with commas.

The following is a list of the declaration instances for some variables. Note that some of the initialization procedures are included.

int A, b, C;         // declares three integers of type int: A, B, C int // declares three integers and assigns an initial value byte z =;         // declaring and Initializing Z string s = "Runoob"  //  declares and initializes the string sdouble//  declares a dual-precision floating-point variable pi char x = ' x ';        // the value of the declared variable x is the character ' X '. 

Second, notes

 PackageCom.hgd.study;/*** variable *@authorHutiger **/ Public classVariables { Public Static voidMain (string[] args) {inta=30;//"A" is the variable "30" is the literal value "=" is the assignment "int" Data type shaping        intB=20; System.out.print (A+B);//and theSystem.out.print (A*B);//Product//---------------------------------        //defining rules for variables        /** 1. Variable name must not be $ _ or the beginning of the letter, you can make $ _ number or character * 2. Variable name suggested first letter lowercase * 3. Variable name cannot use keyword * 4. For multiple English word variables Using the Hump naming method * 5. Variable names not recommended for use in Chinese*/String UserName= "Admin";//String class = "" Error definition    }}

Java Learning notes: Variables for Java