top computer programs

Thinking logic of computer programs (94) and thinking 94 The previous two sections discussed functional data processing in Java 8, which is an enhancement to the container class introduced in sections 38 to 55, it can combine multiple operations on the set data in a pipeline. This section continues to discuss the new features of Java 8, mainly a new class CompletableFuture, which is an enhancement to concur

Thinking logic of computer programs (91) and thinking 91 In the previous sections, we have discussed Java 7. From this section, we will discuss some features of Java 8, including: Passing behavior code-Lambda expressions Function-based data processing-stream Combined asynchronous programming-CompletableFuture New Date and Time API In this section, we will first discuss Lambda expressions. What is it?

Thinking logic of computer programs (36) and thinking 36 In the previous section, we introduced the basic concepts and principles of generics. In this section, we will continue to discuss generics and the wildcard concepts in generics. Wildcards have confusing and confusing syntaxes, but they are widely used in Java container classes. What is it? In this section, let's analyze it gradually. More concise par

Thinking logic of computer programs (68) and thinking 68 This section continues with the content of the previous section and discusses how to use wait/notify to implement more collaboration scenarios. Start at the same time At the same time, it is similar to an athlete's competition. When we hear the game start with a gun, we start at the same time. Below, we simulate this process. Here there is a main thre

Thinking logic of computer programs (87) and thinking 87 In the previous section, we discussed dynamic proxies. in the previous sections, we mentioned ClassLoader for many times. This section will discuss in detail the class loading mechanism and ClassLoader in Java. ClassLoader is the Class for loading other classes. It is responsible for loading bytecode files to the memory and creating Class objects. Lik

Unnecessary programs in Windows How to prohibit the operation, the computer after a period of time will appear some unnecessary procedures, will affect the speed of our computer, if you do not need to prohibit these programs to start on it. But how to forbid it? The following three networks tell you the specific steps.

Thinking logic of computer programs (51) and thinking 51 The previous section describes EnumMap. This section also describes the implementation class EnumSet for the Set interface of the enumeration type. Similar to EnumMap, there is a special implementation class for enumeration types, mainly because it can implement the Set interface very efficiently. The implementation class HashSet/TreeSet of the Set in

file.Continuous read-only code snippets and read-write data segments, which makes it easy for the loader to page and initialize contiguous areas.At load time, the read-only code snippet and the writable data segment corresponding to the page table are initialized to a page that is not cached (involving the operating system and the principle of composition), pointing to somewhere in the destination file on disk. So, during the program loading process, there is no real load of code and data from

Looking for prime factorsRequires the Smallest-divisor process in the book to find the minimum factor of 199, 1999, 19999.Scheme Code:Main process:Define the process of finding prime numbers 4 , greater than the test value, then it must be a prime number can and 2 Divisible, then not prime, the minimum factor is 2 If not, go back to the process Find-div, and then try to divide it with 2+1, loop #lang Racket (define (square x) (* x x)); Definition filter (define (smallest-div

"); This.filelock = This.randomAccessFile.getChannel (). Trylock (); if (This.fileLock.isValid ()) {return true; } else {return false; }} else {return false; }}/** * Unlock and deleteFILE * * @return * @throws IOException */public Boolean unLock () throws IOException {if (!this. File.exists ()) {return true; } else {if (this.filelock! = null) {this.fileLock.release (); } if (this.randomaccessfile! = null) {this.randomAccessFile

This section 1. Some traditional methods2. Generate a QR code image from the program code.3. Scan the generated QR code on your mobile phone and convert it to a py script.Preface Writing scripts on the most mobile phone is a hard task. Although SL4A provides us with the API Quick insertion function, in addition, the elegant Python saves us the trouble of entering semicolons and parentheses, but it does not have intelligent awareness, no keyword completion, narrow buttons, and difficult to enter

The function of an ordered pair is to store two values and then provide again as neededPAIR = x {-y {-f {f[x][y]}}}left = p {p[-x{, y {x}}]}right = p {p[-x{y {y}}]}When I read the first time, I did not understand these lines of Ruby code, and I wrote a JavaScriptPAIR = function (x) {return function (Y) {return function (f) {return F (x) (Y)}}}left = function (p) {return P (function (x) {return function (y) {return x}})}right = function (p) {return P (function (x) {return function (y) {return y}}

Many friends may think that after the Win7 32-bit system is turned on, only we open the program is the start of the program, in fact, you may wish to try to open the computer's Task Manager window, in the process of this column is not to see a lot of content, actually these are currently starting in the program, that is to say, Many programs are open when we open the computer, then in many

Thinking logic of computer programs (5), thinking Logic Intuitive fact violations The reason why a computer is called a "computing" machine is because it was invented mainly for computing. "computing" is of course its specialty. In everyone's impression, computing must be very accurate. But in fact, even in some basic decimal operations, the calculation results a

corresponds to Java.In 32-bit format, 1 bits represent the symbol, 23 bits represent the mantissa, and 8 bits represent the exponent. In 64-bit format, 1 bits represent the symbol, 52 bits represent the mantissa, and 11 bits represent the exponent.In the two formats, in addition to the normal number, the standard also specifies that some special binary forms represent some special values, such as negative infinity, positive infinity, 0,nan (non-numeric, such as 0 times infinity).The IEEE 754 st

Thinking logic of computer programs (67) and thinking 67 The previous section introduced the problem of competing multiple threads to access the same resource and the solution synchronized. we mentioned that in addition to competition among multiple threads, mutual collaboration is often required, this section describes the basic mechanism of multi-thread collaboration in Java. What scenarios need collabora

stack frame was just destroyed. Later, if the program assigns a value to *p, it may actually be modifying the data in another function stack frame, potentially with disastrous and confusing consequences.9. Referencing data in a free heap blockA typical error is referencing data from a heap block that has been freed, for example:[CPP]View PlainCopy int * HEAPREF (int n, int m) { int i; int *x, *y; x = (int *) Malloc (n * sizeof (int)); / * Various operations * / Free (x);

conditional expression:Each p (condition) is evaluated in turn, and the value corresponding to the first condition that is not false is evaluated with its value as the entire cond expression.(cond ( 1>) ; (…( )Expressions such as PN (to find a true or false value) are called predicates.It can be written in scheme: (define (abs x) (cond (> x 0 ) x) ( (= x 0 ) 0 ) x 0 ) (- x) ) ) ) In addition to predicates such as >=(And ...) Evaluates e one at a-until an e is calculated,

At plans to run commands and Program . The at command can only be used when the "scheduler" service is running. If you use it without parameters, at lists the scheduled commands. SyntaxAt [\ computername] [{[ID] [/delete] |/Delete [/Yes]}] At [[\ computername] hours: minutes [/interactive] [{/every: Date [,...] |/next: Date [,...]}] command] Parameters\ ComputernameSpecify a remote computer. If this parameter is omitted, the at program plans c

then sleeps for a while, then sets shutdown to true and finally outputs "exit main".The expected result is that all two threads exit, but actually executes, it is likely to be found that Hellothread never exits, that is, in the Hellothread execution flow, shutdown is always false, even if the main thread has changed to true.What's going on here? This is the memory visibility issue. In a computer system, in addition to memory, the data is also cached