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invocationRecursion: a call to itself within a method is called a recursive　　The entire method executes in memory as shown in the procedure:　　Example: Using recursion to calculate the number of the 5th Fibonacci sequence1/* Calculates the 5th Fibonacci number */2/* 3 Fibonacci Sequence features: F (1) =1,f (2) =1,f (3) =f (1) +f (2), f (4) = (F2) + (F3) ... In turn. 4 that is, the last number is equal to the sum of the first two numbers, such a sequence is the Fibonacci sequence. 5 */6//7 use r

that time, the new supported content will continue to be cached. Set short freshness for parent content : To make the previous pattern work correctly, the contents of the container class should be set to a short freshness period, or not all cached. This is usually an HTML page that is used in other assistance content. This HTML page will be downloaded frequently, allowing it to respond quickly to changes. The supporting content can therefore be cached as much as possible. The key i

Spring MVC request parameter received 1. Receive request parameters via @requestparam2. Object binding to request parameters using PojoRequest:http://127.0.0.1:8080//myspringmvc01/user/save?username=jackuserage=11address.province=anhui Address.city=chuzhouPOJO User: Public class User { private String userName; Private Integer userage; Private address address; // ........... }POJO Address: Public class Address { private String province; Private String City; /

(Object obj) {if(! (objinstanceofStudent))Throw NewRuntimeException ("not a student."); Student stu= (Student) obj;if( This. Zongreturn 1;Else if( This. Zong==stu.zong)return This. Name.compareto (Stu.name);return-1; }}class studentinfoutil{ Public StaticSetgetstudents()throwsIOException {BufferedReader bur=NewBufferedReader (NewInputStreamReader (system.in)); String line=NULL; SetNewTreeset while((Line=bur.readline ())! =NULL) {if(Line.equals ("Over")) Break; String[] Info=line.split ("

first, what is the reflection mechanismIn simple terms, the reflection mechanism refers to the ability of a program to obtain its own information at run time. In Java, as long as the name of the given class,You can then use the reflection mechanism to get all the information about the class. second, where to use the reflection mechanismSometimes we use some knowledge, but we don't know what the terminology is, and when we just learned JDBC we used a line of code,class.forname ("Com.mysql.jdbc.Dr

StringBuffer =NewStringBuffer (text); - System.out.print (Stringbuffer.reverse ()); the } - -}The results of the operation are as follows:3. Convert a string to byte[], byte[] is to store each character of the string as a byte type, but not a char type. So there is no direct reverse output (not like 1). However, we can convert the string to byte[] , and then we can exchange the elements in the end of the symmetry, so that the reverse output is achieved:1 Packagehimi.hebao05;2 3 Publi

{ -System.out.print (""); + } A } at System.out.println (); - } - /*print the lower half of a diamond triangle the middle row is common so the number of rows is Length-1*/ - for(inti = length-1; i > 0; i--) { - for(intj = 1; J ) { -System.out.print (""); in } - for(intK = 1; K ) { to if(k = = 1 | | k = = 2 * i-1) { +System.out.print ("*"); -}Else { theSystem.out.print (""); *

//System.out.println (Rt.freememory ()); System.out.println (Rt.totalmemory ()); try { //process java.lang.Runtime.exec (String command) //execute an external program as a sub-process //rt.exec ("notepad") of the current program; You can also use exec to compile the source files for Java. rt.exec ("Javac Hello.java"); Process p = rt.exec ("java Hello"); InputStream is = P.getinputstream ();//Get in

1. Create1) can be created by assigning values2) can be created by floating-point string3. By using fractions, it is possible to perform certain values accurately, rather than due to the accuracy of floating-point numbers, resulting in differencesRight here, thank you.------------------------------------------------------------------Click to jump 0 basic python-CatalogueCopyright NOTICE: This article for Bo Master original article, without Bo Master permission not reproduced.0

both ends of the communication.* Network communication is actually the communication between sockets.* Data is transmitted via IO between two sockets.* *//** Network Programming:*1 Network Model:*OSI Reference Model:*TCP/IP Reference Model:* 2. Network communication elements:* IP Address:* Port number:*Transport protocol:*3. Define the communication rules:*Language is different, communication needs rules, this rule is called protocol.*The international organization defines the universal protoco

the class and function are, making it clearer' guessnum.py--guess number game ' Import Randomimport time# build the game's core gameplay class core (object): ' Core--core class ' version=1.0 def guessnum (self): ' Guessnum--guess digital Core method ' Try:secret=random.randint (1,100) #生成随机数 #print (Secret) time=6# guess number of times guess=0# input number minnum=0# minimum random number maxnum=100# max random number print (" ---------Welcome to the place where you g

elements is sufficient, but the program sometimes needs to process 200 elements. For security purposes, an array containing 200 elements is used. In this way, the program wastes memory in most cases. OOP makes the program more flexible by deferring such decisions to the run stage. After the program runs, you can tell it requires only 20 elements, and you can tell it requires 205 elements next time.In summary, when using OOP, the programmer may determine the length of the array at run time. To u

1. Truth test* Any non-0 numeric or non-empty objects are true* Number 0, empty object, and special object none are all fake.* Comparisons and equivalence tests are recursively applied to data structures* Comparison and equality tests will return TRUE or False* Boolean and and OR operators return TRUE or false operandsX and Y: if x and Y are true, it is trueX or Y: if x or Y is true, it is trueNot x: If x is false, it is trueAbove are some special examples:Because empty lists, tuples, and dictio

enter the number is:", guess) if Guess==secret: print ("guessed right, really bad") else: # When not equal, you also need to print out the corresponding interval, making it easier for users to use if GuessThis time the game is quite perfect, but it can only provide a user to play, we will introduce the next lesson to the listSo as to realize the function of multi-user guessing.This is the section here, thank you.--------------------------------------------------------

Back to our game today, we add conditional judgment statements to our game and enrich gameplayOur previous code:Print ("---------Welcome to the place to guess the numbers, start---------") #输出提示guess =int (Input ("* Number range 0-100, enter the number you guessed:")) #读取输入, and then assign print (guess) # Print inputThe above is our previous code, relatively simple, just print the number you entered, forget it.We're in there today to add conditional judgments that make the game rich dot1. First

class. For objects associated with soft references, only when the memory is lowThe JVM will not recycle the object. Therefore, this is a good way to solve the problem of oom, and this feature is well suited for caching: such as Web caching, image caching, and so on. 3). Weak references (WeakReference): Weak references are also used to describe non-required objects, and when the JVM is garbage collected, the objects associated with the weak references are reclaimed, regardless of sufficient mem

occurs. - Private Static Final LongSerialversionuid = 1L; + PrivateString name; A Private intAge ; at //static members belong to a class and cannot be serialized. - Private Static intcount; - //transients cannot be serialized either. - transient Private intkey; - - Person () { inSYSTEM.OUT.PRINTLN ("Null parameter constructor"); - } to PublicPerson (String name,intAge ) { +System.out.println ("Parametric constructor"); - This. Name =name; the

derives from C + +, but omits all the incomprehensible features in C + +, such as header files, pointers, structures, cells, operator overloads, virtual base classes, and so on.portability: written programs can be run without modification on Windows, MacOS, UNIX and other platforms to "write once, run everywhere."Object-oriented: Java is a fully object-oriented language.Explanatory: Java interprets Java code by running the Java interpreter on different platforms (Java has a corresponding interp

Len (s) Request length "A%s parrot"% kind String formatting expressions "A {0} parrot". Format (Kind) Method of String formatting S.find (' xxx ') Search S.rstrip () Remove spaces S.replace (' xxx ', ' xxx ') Replace S.endswith (' xxx ') End With XXX ' xxx '. Join (Strlist) Entry and exit separators S.encode (' latin-1 ') Chan

Static memory allocation and dynamic memory allocation in C + +:1. The static object is a variable with a name, we manipulate it directly, and the dynamic object is a variable with no NameWe manipulate it indirectly through pointers. (Static memory allocation is because when the source code is compiled, the compiler allocates memory space for the variable instead of allocating memory when the program executes, and dynamic memory allocation allocates memory when the program executes).2. The alloc