A variable
1. Notes:
In the same "scope", the variable name must be unique, but variables can be reassigned.
2. What is the scope?
A: The description is valid range of variables, within the scope of that can be accessed as long as the scope can not access (that is, the job in large brackets)
3. classification of variables
(1) Local variables: variables declared in the method body;
(2) member variables: variables declared in vitro.
4. In a different scope, the variable name can be the same; the same scope, the variable name is not the same name, java satisfy the principle of proximity. Class body can not write directly to java statement, except to declare variables.
Second, the data type
1. The data type of action
Program which has a lot of data, each data are all data types, different types of data footprint size. Role is to guide the data type of JVM when running a program to allocate how much data memory space.
Data type comprises two 2.java
(1) The basic data types
(2) reference data types
3. With regard to basic data types
Eight subcategories, including four major categories:
The first type: integer byte \ short \ int \ long
The second category: float float \ double
The third category: Boolean boolean
The fourth category: The type char
Third, the source code:
2.CSDN: https: //blog.csdn.net/weixin_44630050 (Xi Jun Jun Moods do not know - Rui)
3. Park blog: https: //www.cnblogs.com/ruigege0000/
4. Welcomes the focus on micro-channel public number: Fourier transform, backstage reply "gifts" to get big data learning materials
