dell 2 in 1 review

1. Preface InArticleBefore getting started, I wrote some nonsense and wrote five articles about the design pattern. The following article is a periodic summary and reflection of the above five articles. First of all, I would like to thank winter-CN for pointing out one error after another in the design mode application. Without him, I will continue to make many mistakes. In addition, I would like to thank many park frie

class name can be called.After the method is static, it is easy to use, but the class can also be used by other programs to establish objects, in order to be more rigorous, forcing the class cannot establish objects, you can do this by privatizing the constructor .Person p = new person ("Zhangsan", 20);What has been done in this sentence?1. Because new uses Person.class, the Person.class file is first found and loaded into memory.

Java review Summary 2 static methodStatic MethodLike static variables, we can also use static methods, called static methods or class methods.In fact, the main method we have been writing is the static method.Static members of the same type can be called directly in static methods, but non-static members cannot be called directly.To call non-static variables in a static method, you can create a Class Object

Introduction: PWM for a lot of software engineers may be familiar and unfamiliar with PWM to adjust the LED brightness For example, its essence is in every period of cutting corners, the overall performance of the LED under-voltage brightness of different effects. As you can see the seven color lantern its principle is similar, just with 3 PWM control red, green, blue three colors of the lamp output brightness, and then combined with the principle of mixing color to show the colorful effect ~Wri

return {};4 Else if(expencted = =Actual)5 return{"Functionx","OK"};6 Else 7 return{"Functionx", expected, actual};8}1 int arr[]; 2 int *p1[]; 3 int (*P2) [P2] is a pointer to an array of 10 integers3.assert preprocessing macro is actually a preprocessing variable that behaves like an inline function, and the Assert macro uses an expression as his condition: assert (expr); First, if

operator:P rintf ("Odd \ n");Bitwise operation AAMP;1?PRINTF ("Odd!\n"):p rintf ("even \ n");Writing a binary output function H.char character occupies 3 bytes, cannot use char I. Array special declaration, definition method int ages[5] = {[2] = 4, [4] = 1};int count = 5;int Ages[count]; Error: int D[count] = {1,2,3,4,5}; The array size must use a constant array

3. Java operatorsMonocular multiplication is the relationship, and the logic is assigned after three eyes.Monocular: monocular operator +– (negative) + +--! such asMultiplication: Arithmetic monocular operator */% +-As: Displacement monocular operator Relationships: Relational Monocular operators > Logic: Logical Monocular operators | | | ^Trinocular: Three mesh single-mesh operators a > B? X:yAfter: Meaningless, just to make up the number of wordsAssignment: Assigned value =　　For example 12 =

name as expressionCreate default Sex_default as ' woman 'Use default values:Sp_binddefault sex_default, ' Mag_emp.sexinfo 'To view the default values:Sp_helpconstraint mag_empTo dismiss the default value:Sp_unbinddefault ' table name. Column name ', ' default value 'Sp_unbinddefault ' Mag_emp.sexinfo ', Sex_defaultDelete default values:Drop Default Sex_defaultTwo methods for implementing data integrity are compared:1. Object level different database

Android Development Review notes-TabHost component (2) (bottom menu navigation), Android tabhost In the previous article "android Development Review notes -- TabHost component (1) (implementing the bottom menu navigation)", we mentioned using custom View (ImageView + TextView) to set the style of a bottom menu. Here we

1 short circuit with , when the left is false, do not execute to the right;Short Circuit or | |, when its left is true, does not execute to the right.2 int a=1;if (a++==2) {A = 7;}System.out.println (a);The output is 2, because when + + is on the right side of a, the first t

row to form an entity, and a number of correspondence between entities and entities The example here is similar to a class in object-oriented, except that it focuses only on the data (fields) that describe the object, not on the object's behavior (function) V. Concepts in the Database Database, non-homogeneous data should be placed in a different database (1) Facilitate personalized management of individual data categories (

Android Development Review notes-TabHost component (1) (implement menu navigation at the bottom), Android tabhost What is TabHost?The main function of the TabHost component is to manage applications by category. For example, you can see a graphical interface when using a windows operating system. When talking about this component on the TabHost tab, you have to go over the API provided by Google. We can fin

2015-10-20Before learning Java knowledge, just follow the code used to jump to learn some, not all of the learning is also wrong into pieces ... Well, what a tragedy!Reasoning, it is necessary to review and finishing, otherwise written out of things really can't read. So, from today's 1.1-point gnawing down.Back to the creation of the class file, and see the familiar main function ... Then, there is the question of the title. So, let's

same length, two corresponding binary is 1, the result value of this bit is 1, otherwise 0.ShiftA shift is a two-dollar operator used to move each bit in a binary number to One direction, and the overflow part is discarded, and the vacant part fills in a certain value. In the Class C language, the left shift uses two less than the symbol "The logical shift (either left or right) is 0 of the vacancy. Th

Review Inside The C ++ Object Model (2), insidethegirls // Constructor/non-constructor difference class Foo {public: // Foo (): val (0), next (NULL) {} int val; Foo * next ;}; void foo_bar () {Foo bar; if (bar. val bar. next) {cout "Member Class Object with Default Constructor" (1) If class A contains one or more member-class-objects, each constructor of class A

different from traditional programs, and Sun is introducing Java as an open technology. Tens of thousands of Java development companies around the world are required to design Java software that must be compatible with each other. "The Java language relies on the power of the community rather than the power of the company" is one of Sun's slogan, and has been recognized by the vast number of software developers. This is completely different from the focus on the elite and the closed model advoc

Mysqlsql Statement Review 2 -- Regular Expression Here, we will briefly review the usage of Regular Expressions in mysql when filtering data. This mainly refers to an example for each usage or a brief description. The REGEXP keyword is used to filter data using regular expressions. Basic character match: SELECT prod_name FROM products WHERE prod_name REGEXP '2013

of update loss issuesTwo concurrent transactions are modified based on the same query result.Subsequent transactions ignore the impact of the first committed transaction on the database, resulting in the loss of the impact of the first committed transaction on the database.This process is called update loss.Optimistic and pessimistic locks are not the real locks in the database, but the names of the two solutions.(1) Pessimistic lock: Pessimistic thi

valid data type, so only the name of the class can be used as the name of the pointer. For example:CRectangle * prect;is a pointer to an object of class Crectangle type.Just like in the case of a data organization, you need to use the operator---to directly refer to a member in an object that is pointed to by a pointer. Here is an example that shows several possible scenarios: //pointer to classes example #include A area:2*b Area:

an abstract class and an interface?(1) Abstract classes need to be inherited, and can only be inherited. Interface needs to be implemented, and can be implemented more, that is, to implement multiple interfaces(2) Abstract classes can be defined abstract methods and non-abstract methods, subclass inheritance can directly invoke non-abstract methods, the interface can only define abstract methods (that is,