20145321 Java Programming 2nd week of study summary

20145321 "Java Program design" The 2nd week study Summary textbook Learning content Summary

Type, variable, operator

1. Type (basic type)

(1) Integers: Short (2 bytes), int (accounting for 4 bytes), Long (8 bytes) three kinds. The greater the number of integers, the larger the integer range that can be represented by the integer type.

(2) Byte: Byte type (1 bytes). An integer that represents the -128~127 when used to represent an integer.

(3) floating point number: Mainly used to store decimals, divided into float (4 bytes), double (8 bytes).

(4) Character: char type (2 bytes), used to store character symbols such as ' Z '.

(5) Boolean: Boolean type, which represents true and false.

(6) Annotation://single-line annotation;/**/multiline annotation.

2. Variables

(1) If you want to declare what type of variable, use int, byte and other keywords to declare. Do not start with a number, and do not use special characters. Named by: "Hump-type" nomenclature, such as "int ageofstudent".

(2) Final: Declare a variable with final qualification to prevent yourself or others from inadvertently modifying it.

(3) Ignore symbol \: If you want to represent only one character, add this character after \, such as \ '.

(3) 0b means binary, 0 means octal, and 0x means 16 in. When you represent a longer number, the underscore is used to make the expression clearer. such as int a=1234_5678.

3. Operators

(1) Arithmetic operations: +,%, etc.

(2) comparison, conditional operation:>, = = (judgment, and = is the specified operation), 1? 2:3 ET

(3) Logical Operation:&&, | |,!

(4) Bitwise arithmetic:&, |, ~ (sense should be anti-code), ^ (XOR), <<, >>, >>>

(5) Increment decrement operation: i++ 、--I, etc.

(6) Specify operation: + =,/=, etc.

Second, type conversion

Note that when you write a program, type conversions, such as 3.14, are default to double, and you need to add f:3.14f after you want to define float. If different types are included in an expression, the operation is dominated by the longest type.

Third, Process Control

1. Branch: If...else;switch...case

2. Circulation: For;while;do...while;break\continue

Problems in teaching materials learning and the solving process

1, what is the difference between printf and println, when using to distinguish? Another printf ("0 and 0%5d%n", 0 & 1), feel the comma after the content and C language slightly different, after the code to feel more.

2, the specified operation does not know whether to learn C language ignored, feel this content unfamiliar, but it is very convenient, it should be able to use well.

Problems in code debugging and the resolution process

After-school operation question 1

Problem: No results

Did not hit%d

To modify the results

Other (sentiment, thinking, etc., optional)

Or more dozen code more practice to skilled use, and C language can be compared to learn, should be able to learn Java better.

Learning progress Bar

	Lines of code (new/cumulative)	Blog volume (Add/accumulate)	Learning time (new/cumulative)	Important growth
Goal	3500 rows	28 Articles	300 hours
First week	150/150	1/1	20/20
Second week	200/350	2/2	40/40
Third week
Week Four

20145321 Java Programming 2nd week of study summary