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@private: Private, only the object method in this class can access it directlyA member variable is defined in that class to be used in that class@protected: Protected: Can only be accessed directly in this class and subclass, no longer externally accessible@public: Public, everyone can use, in this class, sub-class, external can be accessed@package: Mainly used within the framework, within the framework equivalent to @protected, outside the frame equivalent to @private (understand)This class: A

Stacks: Local variables: Variables defined inside a method or functionSystem ManagementHeap: Dynamic Storage AreaGenerally by the program ape Management# # Reference countIf memory management is inappropriate1, no longer use objects are not recycled, memory leaks, resulting in program flash2, is being used object is released, wild pointer, access to the wild pointer will cause the program to crashARC Automatic Reference Counting Auto Reference countMRC Manual Reference Counting Manual reference

Local variables, member variables, and global variables1. Inside a method, you can define a local variable with the same name as the member variable.So within the scope of this local variable, he overrides the member variable.2, if the definition and member variables with the same name as local variables, but also (ˇ?ˇ) want to manipulate local variables;3, global variables, the entire file sharing, all methods shared;A method that modifies this global variable in other ways uses this global var

getinstance () { return s; } } 2, lazy type: It is the characteristics of the object is called when the method is initialized, which is also called the object's delay loading. For example: In the following complete code, the single class enters memory, and the object has notexists, the object is created only when the getinstance () method is called.The complete code is as follows: Class single { private static single s=null; Private single () {} public Static

parent class methodpublic void Alldraw (Quadrangle quadrangle) {Quadrangle.draw;} Quadrangle.alldraw (square); Quadrangle.alldraw (parallelogram);Inherit the parent class quadrangle to Suqare and parallelogram.It then uses the Quadrangle class format to format the array, then assigns the arguments of the child class object to the object of the parent class, and the draw () method for outputting each element with foreach.---------------------------------------------------------------------------

, servletexception {System.out.println ("Filterdemo1....before"); Chain.dofilter (request, response); System.out.println ("Filterdemo1....after");} Filter objects when they die, the aftermath works. public void Destroy () {}}Package Cn.itheima.filter;import Java.io.ioexception;import Javax.servlet.filter;import javax.servlet.FilterChain; Import Javax.servlet.filterconfig;import Javax.servlet.servletexception;import javax.servlet.ServletRequest; Import Javax.servlet.servletresponse;public class F

: After the () of the method.Attention:Don't throws if you can try...catch.However, at present lectures for convenience, I all throws.(5) What is the difference between a compile-time exception and a run-time anomaly?A: The compile-time exception must be processed.B: Runtime exceptions can be handled or not handled.(6) The difference between throws and throw?A:throwsLocation: After the method (), followed by the class name.If the following is based on RuntimeException and its subclasses, then th

establishment of a buffered character stream object, the existence of a stream object first.BufferedReader Unique method: public string ReadLine ();//read one line at a time, and return the character data before the row tag as a string when the row is marked. When the end is read, NULL is returned.BufferedWriter Unique method: Publicvoid newLine ();//write the platform-related line delimiter to mark the end of a line. The Windows platform is ' \ n '. Copyright NOTICE: This article for Bo Master

(SocketAddressendpoint) This socket to the server. Connect connect(SocketAddressendpoint, inttimeout) This socket to the server and specify a timeout value. getInetAddress() Returns the address of the socket connection. getLocalAddress() Gets the local address of the socket binding. getPort() Returns the remote port that this socket is connected to. isClosed() returns the closed state of the socket. isConnected() Returns the connection state of the socket. toString() Convert this socket to

bufr = new BufferedReader (new InputStreamReader (system.in)); String line = null;while (line = Bufr.readline ())!=null) {byte[] buf = line.getbytes ();D atagrampacket dp = new Datagrampack ET (Buf,buf.length,inetaddress.getbyname ("192.168.3.4"), 10103);d S.send (DP), if ("over". Equals (line)) { SYSTEM.OUT.PRINTLN ("Chat program exit"); Break;}} Ds.close ();} catch (Exception e) {System.out.println (e.tostring ());}}} Class Rece implements Runnable{datagramsocket DS; Rece (Datagramsocket ds

Object wrapper class new featuresThe new feature in the JDK1.5 version is that objects can be directly operated between values. As follows:4// 直接将4赋值给整型对象x，称为自动装箱，等同new Integer(4)2//直接运算，x + 2自动拆箱，然后再将和自动装箱，并赋值给xnew2//x = x + 2的具体过程。Integeris int more than one value null . There are some of the following features:128128127127;System.out.println(m == n);System.out.println(a == b);The result is as follows, because when the value of integer is within the range of byte, if the value already exists

constructors. In the class, constructor getdeclaredconstructor (class... C) can independently obtain the private constructor. 　　　　 Run the constructor: Object newinstance (object... O) in the constructor class) If setaccessible (Boolean 0) in the accessible class of the parent class of the constructor class is true, the JVM access check is canceled during the runtime to run the private constructor. In the class, object newinstance () can directly obtain and run the constructor of the public-mod

--- Java training, Android training, IOS training, and. Net training. We look forward to communicating with you! --- Design two classes and write out the set get method corresponding to the attribute (write method only) 1> Vehicle (1) attributes * Number of wheels * Speed (2) Method * Set and get methods corresponding to the attribute The Code is as follows: 1 // setter getter Declaration 2-(void) setwheels: (INT) wheels; 3-(INT) wheels; 1 // setter getter implementation 2-(void) setwheels; (INT

--- Java training, Android training, IOS training, and. Net training. We look forward to communicating with you! --- 1. Basic concepts of Scope Local variables and global variables have their own scopes, and member variables are no exception. Scope: the scope within which access is allowed. 2. Scope type of member variables @ Public can be directly accessed anywhere @ Protected can be accessed directly in the implementation of the current class and subclass @ implementation. Only the set get met

No.: Notes downloading black horse programmer _ watch video notes _ 1-10 Concept:. netAnd C # L. Net/DOTNET: generally refers to the. NET Framework framework, a platform and a technology. L c # (C sharp): a programming language that can be used to develop applications based on the. NET platform. L (*) Java: A technology and a programming language C sharp indicates sharp. c ++ indicates two well numbers (#)

is usually used to close resources. Finally is not executed in only one case. When it is executed to system. Exit (0); fianlly will not execute. Three formats of the processing statement: First format: // Remember: Catch is used to handle exceptions. If no catch is found, the exception has not been processed. If the exception is detected. It must be declared. Exceptions are embodied in child parent class overwrite; 1. When a subclass overwrites the parent class, if the method of the parent

)) break;byte[] Buff = line.getbytes ();D atagrampacket dp =new datagrampacket (Buff, buff.length, Inetaddress.getbyname ("192.168.0.255" ), 9990);d S.send (dp);}} catch (Exception e) {throw new RuntimeException ("Send-side exception");}}} Class Receiver implements Runnable{private Datagramsocket ds; Receiver (Datagramsocket ds) {this.ds = ds;} public void Run () {try {while (true) {//while loop, ensure this thread does not die byte[] buf = new byte[1024];D atagrampacket dp = new Datagrampacket

+ +, C #, Java, objective-c, etc.Iii. Introduction to C language 1. The reason for learning C language first1) OC based on C2) OC and C's thought and grammar are different in many places, and OC can be mixed with C3) c is the classic of all programming languages, many high-level languages are derived from C language, such as C + +, C #, OBJECTIVE-C, etc.2. Brief History1) The C language was invented in 1972 and was first used to rewrite the Uinx operating system (Unix was written primarily in a

regex = "\\[email protected]\\w+ (\\.\\w+) +"; Pattern P= Pattern.compile (regex);//Encapsulating Regular Expressions//reading Web page data while(line = Br.readline ())! =NULL){ //Regular Correlation DataMatcher m =P.matcher (line); //find a matching mailbox while(M.find ()) {System.out.println (M.group ());//Output Matching mailbox } } } //gets the e-mail address in the specified document. Use the Get feature. Pattern Matcher Public

) NSLog (@ "%d%d", yes,no); Note: OBJECT-C provides a bool type, but this bool type is not the same as in C + +: everything in C + + that is not 0 value Is true, and a value of 0 is false. But Object-c 1 is true and is defined by the macro as yes,0 false and defined by the macro as NO. five, multiple. m file compilation issues 1) Write 3 files Main.m One.h ONE.M 2) Run the command to comp