Chinese name
The code
Foreign names
Code
The operator
Programmers
Define
Development tools support the written language source file
Pinyin
Dai m m:
Hot concern
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Words to explain
For the input data and instructions to automatic computer or tabulator any symbol system; Also refers to the record of the symbols (such as by drilling data by magnetic point on the CARDS or tapes)
Computer code
Source code (also called a source program), refers to a series of human readable computer language instructions,
Source code is relative to the target code and an executable code, source code is written in assembly language and high-level language code, object code refers to the source code is compiled programs can be produced by the CPU directly identify the binary code, executable code is to connect the target code after the formation of the executable file, of course also is binary,
In modern programming languages, the source code can be in the form of books or tape, but the most commonly used format is a text file, this is a typical format in order to compile a computer program, the ultimate goal of computer source code will be human readable text translated into computer can perform binary instructions, this process is called compilation, done by the compiler,
Role
The source function has the following two main functions:
To generate the target code, namely the computer code that can be recognized,
Of software, namely for the writing of the software, the number of beginners, and even a few experienced programmers ignore software instructions to write, because this part is not in the generated program directly, according to also do not participate in the compilation, but the description of software learning, sharing, maintenance and software reuse has huge benefits, therefore, writing software that is considered to be in the industry can create the good habit of good program, some companies are hard and fast rules must be written,
Need to point out that the source code changes can't change the target code have been generated, if you need a change to the target code, must recompile,
Code combination
Source code as a special part of the software, which may be contained in one or more files, a program that don't have to be written in the same format of the source code, for example, if a program with C language library support, you can use C language; And the other part in order to achieve high efficiency, can be written in assembly language,
More complex software, a need the participation of dozens or even hundreds of source code, in order to reduce complexity, must introduce a kind of connection between each source can be described, and how to compile right system, in this context, revision control system (RCS) was born, and become one of the essential tools developers to code revision,
There is another kind of combination: the source code to write and compile points don't implementation on different platforms, a technique known as software transplantation,
Copyright
If according to the different types of source software, is usually divided into two categories: free software and free software, free software are usually not only can get free, and open source code; Corresponding to the non-free software is not open source code, all via abnormal means of non-free software source code will be deemed to be illegal,
Quality
For computer, there is no "good" in the true sense of the source code; However, as a person, the writing habits of good or bad will determine the stand or fall of source code, source code is readable, is an important standard of judging its quality, software documentation is showed that the key to readability,
Although we can use different language to realize the same function of the computer, but there are different on the execution efficiency, the rule is: the more high-level language, its execution efficiency is lower, which is why the assembly language generated file is generated by VB language than generally smaller,
Open source
Most of you purchase or download software only provides the compiled version can be run, "compiled" means that developers create actual program code (called the source code) has been carried out by a special program called a compiler before treatment, the program will the format of the source code into a computer can understand (please see the detailed information about the compiler, C language tutorial), modify the compiled version of the most applications are extremely difficult, people almost impossible to know exactly how developers create all parts of the program, most of the business software maker regard this as a favorable conditions, in order to prevent other firms to copy your own code and its use in the competitive products, at the same time can be controlled with the quality and function of a specific product,
Open source software on the contrary, the source code provided with the compiled version, and the fact that encourage people to modify or customize, support the concept of open source software developers believe that by letting people interested in modify the source code, the application will be more perfect, and for a long time without error,
The software development industry, as defined by the open source software must meet certain conditions:
Program must be free (but can be sold part of the package, such as in the example below, the Red Hat for Linux is to do so),
Must provide the source code,
Must allow anyone to modify the source code,
Can redistribute modified versions,
Permit shall not be required to exclude other software or intervention in other software running,
Let's look at a real example of open source software, in 1991, students at the university of Helsinki, Finland, Linus? Torvalds (Linus Torvalds) based on the derived version of Unix Minix has developed a new operating system, and is called a Linux, Torvalds using the GNU general public license (it is open source software provides a good legal definition) released the 0.02 version of Linux, download and start using Linux, people all around the globe, many users are independent programmers, to provide source code modified Torvalds, over the next three years, Torvalds from other programmers have received the revised version, and combines many changes to the base version, released in 1994 the Linux version 1.0,
Those who want to use open source Software end users a common concern, is the lack of Software quality guarantee and technical support, because of the Software license encourages modification and customization, so almost unable to provide support, this is the Red Hat Software, established in 1994 to create "the Official Red Hat Linux" and sell this is usually the cause of the "free Software", Red Hat to add to the package is the main value of the quality guarantee and technical support, for most enterprises, technical support commitments become prompt it to buy Linux not free download it a key factor, in addition to the Red Hat, there are other companies packaged Linux (usually with other Software) for resale,
Besides Linux, Mozilla browser (Netscape core), Apache (Web server), PERL (Web scripting language) and PNG (graphics file format) is a very popular based on open source software,
WEB standards
WEB standardized CSS + DIV code
CSS + DIV is site standard (or "WEB standards") in one of the commonly used terms, usually to illustrate with HTML (an application of the standard generalized markup language) in WEB design language form (table) positioning mode, the difference between because XHTML WEB design standards, no longer use table positioning technology, but a variety of positioning is realized by using CSS + DIV way,
Cascading style sheet (CSS) foreign language abbreviation, it is a used to represent HTML (an application of the standard generalized markup language) or XML (a subset of standard generalized markup language) file style of computer language, such as
DIV elements are used for large in the HTML document (foreign language block - level) to provide structure and the content of the background elements, between the start tag and the end of the DIV tags all content is used to form the block, including the characteristics of elements contained by the DIV tag attributes to control, or by using stylesheets this block to control the formatting,
CSS + DIV design advantages and problems of
XHTM are advocated by the international standard design language, because XHTML web design language has the basic characteristics of the CSS + DIV model of website design has a certain advantage, but at present in the website construction application CSS + DIV model also has some problems, this paper comprehensive website technology and experience of the designer, and from the perspective of the application of network marketing, the advantage of CSS + DIV website design and problems summarized as follows:
The advantage of CSS + DIV design
First of all, the great advantages of CSS in concise code, for a large site, can save a lot of bandwidth, and it is well known that the search engines like clean code (its real significance lies in the fact that increasing the proportion of the total code page) effective keywords, so using CSS + DIV web standards make web site has a certain advantage of search engine friendly,
Second, CSS + DIV website makes the website redesign is relatively simple, a lot of problems need to change the CSS only and do not need to change the program, thereby reducing the cost of website redesign,
CSS + DIV design problems
Despite the CSS + DIV has a certain advantage, but at this stage the CSS + DIV problems of website construction is more obvious, mainly displays in:
First, for CSS is highly dependent on the web design has become more complex, relative to the form of HTML4.0 layout (table), CSS + DIV although not high, but at least than to form more complex positioning, even for a master website design is easy to appear problem, not to mention a beginner, this to a certain extent, affected the XHTML web design language, to popularize and apply the
Second, the CSS file anomalies will affect the entire site normal browsing, usually made CSS web design elements on several l external file, this one or several files may be quite complex, relatively large and even, if the CSS file called abnormal, then the website will become gloomy,
Third, for the browser compatibility problem of CSS web design is more outstanding, web page design based on HTML4.0 after IE4.0 almost does not exist in the version of the browser compatibility issues, but the CSS + DIV design website normal page in Internet explorer, FireFox browser (FireFox) may recognition (that's why the advice network marketers use FireFox), CSS + DIV has yet to be further support for each browser vendors,
Fourth, CSS + DIV for search engine optimization depends on web design professional level rather than CSS + DIV itself, the CSS + DIV design does not ensure that web page to the search engine optimization, even cannot guarantee a certain than HTML web site has a more concise code design, and the search engine for web page collection and sorting is clearly not in terms of whether to adopt the form and CSS positioning, which is why many traditional form layout of the production site in the search results sorted, and many use CSS and web standards making page rank is still on the reason, because for the search engine, site structure, content, related website links and other factors is always website optimization is the most important indicators,
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