20165225 Java programming Second week of study summary

20165225 "Java Programming" the second week of study summary 1. Video and textbook Learning:

##### 1.标识符：字母、下划线、美元符号、数字（不能是true，false，null还有关键字）。##### 2.关键字：int，double，float。基本数据类型:##### 3.整数类型：byte，short，int，long，区别主要是取值范围不一样。##### 4.字符类型：char，强制转换(int)‘a‘,(char)97##### 5.浮点类型: float(16位，只保持7-8位，float m=12.123456789f)，double(32位，保持15-16位)##### 6.基本数据类型排序:byte<short<char<int<long<float<double级别低的可以转换为级别高的(float m = 100)，级别高的不可以直接转换为级别低的。##### 7.输入数据：创建一个scanner对象 Scanner reader = new Scanner(System.in)Scanner对象调用方法读取用户键盘输入的数据，例：int m =reader.nextInt()##### 8.输出数据：System.out.println("值为："+a);System.out.printf("格式"，值列表);类似于c语言的形式##### 8.声明数组：int [] a;or int a[]创建数组 数组名=new 类型[]a = new int [5]##### 9.数组的长度：一维数组 a.length二维数组，a.length是二维数组中一维数组的个数

Problems encountered in learning:

• 1. The time to knock the code is too dense, knock it out to understand again, very tired.
• Git push failed, later found that there is something on the remote side I do not have, and then lazy to find, direct git push-f forced push up, will be gentle point.
• 3. The night before the preparation of study should not stay up, or the next morning is no.
• 4. Why should I go to Baidu to find the answer to my homework after class?

2. The second to third chapter code (the order is not in sequence):

3. Upload the code to the Code cloud:

• My Code Cloud Link: 20165225-milk Aberdeen.
• Have a nice weekend.

20165225 Java programming Second week of study summary