understanding netflow

Deep understanding of the unit of length in CSS, deep understanding of css Length* Directory [1] px [2] in [3] cm [4] mm [5] q [6] pt [7] pc [8] em [9] rem [10] ex [11] ch [12] ext [13] vw [14] vmin [15] vmax This article introduces the main knowledge of the unit of length in CSS by dividing it into absolute length units and relative length units. Absolute length unit The absolute length unit represents a p

Recently, some good websites have been found in other countries.Article, Collected, sorted, and added to your understanding, recorded as notes, so that you can have memories in the future. ASP. net is a very powerful platform for building Web applications. It provides great flexibility and capabilities so that it can be used to build all types of Web applications. most people are only familiar with high-level frameworks such as webforms and WebServi

First understanding of PHP (4) PDO object configuration and use, first understanding of pdo I. PDO Concept PDO is actually a database abstraction layer. With PDO programming, you can easily change the database at any time in subsequent operations without changing the source code. Shows the location of PDO: Phptest, "root", "123 "); This completes the initialization of the PDO object. The connected database

In-depth understanding of concurrency (1), in-depth understanding of concurrency ( 1. Why concurrency?Perhaps the first reason we think of is to make the program run faster. Indeed, for a multi-processor machine, each task is allocated to multiple CPUs using concurrency, it enables faster program execution.However, when a concurrent program is run on a single processor machine, the cost of context switchin

A deep understanding of the JavaScript series (27): The Builder mode of design patterns, and a deep understanding of javascriptIntroduction In a software system, sometimes it is faced with the creation of "a complex object", which is usually composed of sub-objects of each part using a certain algorithm; due to changes in requirements, the various parts of this complex object often face drastic changes, but

In-depth understanding of the JavaScript series (13): This? Yes, this !, Understanding javascriptIntroduction In this article, we will discuss more details directly related to the execution context. The topic of the discussion is the this keyword. Practice has proved that this topic is very difficult, and this often occurs in different execution contexts. Many programmers tend to think that in programming l

A deep understanding of the JavaScript series (31): the proxy mode of the design mode, and a deep understanding of javascriptIntroduction Proxy, as its name implies, is to help others do things. The GoF defines the proxy mode as follows: Proxy mode, which provides a Proxy for other objects to control access to this object. The proxy mode allows the proxy object to control the reference of a specific object.

W3C understanding: understanding of the relationship between Party discipline and national lawThere are two standards available for website development: W3C or IE, because IE is not compatible with W3C in many places. That is to say, if your website is developed by W3C, there will be issues with IE display, if you develop it based on IE, on the one hand, IE6, 7, and 8 versions are not compatible with each o

Understanding of fork functions and understanding of fork Functions Header file: # include pid_t fork (void); 1. Create a sub-process and return-1 If the sub-process fails.2. Call once and return twice. The child process PID and 0 are returned respectively in the parent and child processes. Using different return values, you can write different processing branches for the parent and child processes respe

DWZ (1): First understanding of the framework and first understanding of the dwz framework The DWZ rich client framework (jQuery RIAframework) is an open-source Ajax RIA framework developed by Chinese people based on jQuery. The design goal of the DWZ rich client framework is simple and practical, easy to expand, fast development, RIA ideas, and lightweight. The DWZ framework supports HTML extension instead

A deep understanding of Java interfaces and abstract classes, and a deep understanding of java Abstraction For object-oriented programming, abstraction is one of its major features. In Java, OOP abstraction can be embodied in two forms: interfaces and abstract classes. There are too many similarities and differences between the two. Many people think that they can be used in different ways when they are ne

the heap, the right side is the memory representation of the function object, the center is the pointing of the prototype attribute of the function object, and the left side is the object instance created by the function object. The function object points to the pointer of the prototype attribute and writes dog1, dog2, and dog3 correspond to three reference changes of Dog. prototype respectively. They also have a relationship with dog1, dog2, and dog3 in the stack. (Note: Function objects will

:\tmemmove with overlap\n" );printf ( "source:\t\t%s\n", string2 + 4);printf ( "destination:\t%s\n", string2 + ten);Memmove (string2 + ten, string2 + 4, 40);printf ( "result:\t\t%s\n", string2);printf ( "length:\t\t%d characters\n\n" , strlen (string2));printf ( "function:\tmemcpy with overlap\n" );printf ( "source:\t\t%s\n", string1 + 4);printf ( "destination:\t%s\n", string1 + ten);memcpy (string1 + ten, string1 + 4, 40);printf ( "result:\t\t%s\n", string1);printf ( "length:\t\t%d characters\n

Today, a small program, I feel that some of the problems are easy to overlook!This program code is as follows:The result of the program is:I think a lot of small white like me may only start to wonder why the final result is 255! First, we need to know that strlen () is a function that calculates the length of a string, but why is the last string length 255? The defined array A does not have 1000 elements, and the For loop is executed 999 times?For Char, we have to know that the implied end tag

The functionality of the scrapy. Third, data processing flowScrapy 's entire data processing process is controlled by the scrapy engine, which operates mainly in the following ways:The engine opens a domain name, when the spider handles the domain name and lets the spider get the first crawl URL. The engine gets the first URL to crawl from the spider , and then dispatches it as a request in the schedule. The engine gets the page that crawls next from the dispatch.The schedule returns the next

Java polymorphism understanding and java polymorphism understanding Implementation of polymorphism in Java What is polymorphism The following are three necessary conditions for the existence of polymorphism, which require that everyone be able to carry out their dreams! Three necessary conditions for Polymorphism1. There must be inheritance;2. There should be rewriting;3. parent class references to child cl

Understanding of JavaScript scopes and block-level scopes, and understanding of javascript concepts Scope is always the top priority of any programming language, because it controls the visibility and lifecycle of variables and parameters. Here, we first understand two concepts: block-level scope and function scope. What is block-level scope? The statement set in any pair of curly braces ({And}) belongs to

A simple understanding of Java exceptions and a simple understanding of JavaWhat is the essence of Java exceptions? Essentially, a java exception is a java Object (inheriting objects). Like a general java Object, it encapsulates some member variables and operations, we can operate java exception objects as we operate on general java objects (I also tried it specially, but can I use the throw keyword to oper

Servlet's personal understanding, Servlet's personal understanding 1. What is Servlet? 1. servlet is a dynamic web page technology based on Java technology. It runs on the server side and is managed by Servlet containers to generate dynamic content. It is very complicated for jsp (servlet to develop web pages, so now it is generally used for process control. Supplement: jsp: the framework of jsp is HTML. It

Object-oriented Exception Handling: an in-depth understanding of java exception handling mechanism, and an in-depth understanding of Exception Handling What is an exception? An exception is a description of the problem. It encapsulates the problem object;Characteristics of the exception system: all classes and objects in the exception system;Can be throttled, that is, it can be operated by the throw and thr