199 1 year, Microsoft Corporation of the United States introduced Visual Basic (VB for short), and the latest version is Chinese VB 2005(VB8).
Vision means seeing, seeing, and refers to the method of developing a graphical user interface (GUI) similar to windows operating system. It doesn't need to write a lot of code to describe the appearance and position of interface elements, just drag and drop the pre-established objects to the corresponding positions on the screen.
Basic refers to the founder and beginner of the universal symbolic instruction code language.
Visual Basic has three versions: learning version, professional version and enterprise version, which meet different development needs. The learning version is suitable for ordinary learners and most people who use Visual Basic to develop ordinary Windows applications, but; The professional edition is suitable for computer professional developers, including all the content functions of the learning edition and advanced functions such as Internet control development tools. In addition to all the contents of the professional edition, the enterprise edition also has tools such as automatic component manager, which allows professional programmers to develop powerful distributed applications in groups.
VB is a visual, object-oriented and event-driven structured high-level programming language, which can be used to develop various applications in the Windows environment. It is easy to learn, efficient and powerful, and can be compared with Windowsr's professional development tool SDK. In the Visual Basic environment, by using the event-driven programming mechanism, the novel and easy-to-use visual design tools, the rich application program interface (API) functions in Windows, and the technologies such as dynamic link library (DLL), object linking and embedding (OLE) and open data connection (ODBC), the application software system with powerful functions and rich graphical interfaces can be developed efficiently and quickly. With the improvement of the version, the functions of Visual Basic are getting stronger and stronger. After version 5.0, Visual Basic came out in Chinese, and compared with the previous version, its functions have been greatly improved.
2 1 At the beginning of the century, great changes have taken place between Visual Studio 2003 introduced by Microsoft and Visual Basic. Visual Studio provides a platform for various programming tools, and Visual Basic.NET can run on this platform. Compared with traditional VB, it is very different. VB.Net used it. Net framework for visual programming, and is well compatible with COM framework. In 2005, Visual Studio 2005 used the technology of NET 2.0, which brought more convenience to programmers. However, the new program also needs higher system configuration and the support of Microsoft. Net framework above 2.0.
In addition, VB(V stands for vitamin) has another meaning: vitamin B.
Vitamin B includes vitamin B 1, vitamin B2, vitamin B6, vitamin B 12, nicotinic acid, pantothenic acid and folic acid. These B vitamins are indispensable substances for promoting metabolism and converting sugar, fat and protein into heat. If vitamin B is lacking, the cell function will immediately decline, causing metabolic disorder, and then the human body will be depressed and lose appetite. On the contrary, excessive drinking can lead to liver injury, which is closely related to vitamin B deficiency in many cases.
The following foods are rich in vitamin B:
① Foods rich in vitamin B 1: wheat germ, pork leg, soybean, peanut, pork tenderloin, ham, black rice, chicken liver, germ rice, etc.
② Foods rich in vitamin B2: eel, beef liver, chicken liver, mushrooms, wheat germ, eggs, cheese, etc.
③ Foods containing vitamin B6, vitamin B 12, nicotinic acid, pantothenic acid and folic acid: liver, meat, milk, yeast, fish, beans, egg yolk, nuts, spinach, cheese, etc. Vitamin B 1 cannot be stored in human body, so it should be supplemented every day.
It is difficult to get all the B vitamins, but it is simple and convenient to get them through careful food selection. The above foods containing vitamin B can be divided into two groups: ① and ②. Looking at the above classification, we can see that ② and ⑧ are both contained in roughly the same food. Therefore, ① as a group of foods, ② and ③ are combined into a group of foods, and two groups of foods are selected in combination, so that the B vitamins can be basically held in your hand.
VB has a third meaning.
valence bond theory
valence bond theory
A processing method to obtain approximate solution of molecular Schrodinger equation. Also known as electronic pairing method. The earliest chemical bond theory in history. This paper mainly describes covalent bonds and covalent bonds in molecules, and its core idea is that electrons pair to form localized chemical bonds.
1927, W. H. Hai and F. W. London first completed the quantum mechanical approximation of electron pair bonds in hydrogen molecules, which is the basis of near-cost bond theory. L.C. Pauling and others developed it, introduced the concept of hybrid orbitals and the complete valence bond theory, and successfully applied it to the structures of diatomic molecules and polyatomic molecules.
Valence bond theory is a generalization of London's method of treating hydrogen molecules. The main points are as follows: ① If two atomic orbits overlap each other and there is an electron on each orbit, and the spin directions of the electrons are opposite, then the electron pairing gives a singlet state and forms an electron pair bond. ② After two electrons are paired, they cannot be paired with the third electron, which is the saturation of covalent bonds. (3) Following the principle of maximum overlap, covalent bonds form bonds along the direction of maximum overlap of atomic orbits. Covalent bonds have directionality. Atomic orbitals usually have a maximum in a certain direction, and only in this direction do they have the maximum overlap, forming covalent bonds. Different atomic orbitals have different bonding abilities. The maximum value of atomic orbit is a measure of the bonding ability of atomic orbit. Pauling gave the bonding ability of atomic orbitals such as S, P, D and F as 1, 3, 5 and 7 in turn. When the principal quantum number is the same, the covalent bond formed by the orbit with high bonding ability is stronger.
Valence bond theory is consistent with the classical concept of electron pair bond that chemists are familiar with, and it developed rapidly as soon as it appeared. However, the calculation of valence bond theory is complicated, which makes the later development slow. With the improvement of computing technology, the theory will have new development.
In Ethernet technology, VB is called: virtual bridge.
In fact, VB is the division of management domains for the convenience of management, which is equivalent to a virtual L2 Lanswitch. In the application of MAN, VB is based on user division. That is, each user has his own independent VB, which contains multiple vlan tags and mac addresses. Because Vbs are isolated from each other, different Vbs can allocate the same vlan without affecting each other, while L2 chip based on VB vlan division cannot distinguish the same VLAN of different users.
What is 1.VC? What is learning VC?
First of all, VC is a software (IDE integrated development environment) (compilation, editing and debugging).
C and C++. But some features in C++ are not used, such as I/O flow and polymorphic inheritance.
WindowsSDK (software development tool)
Soul of VC: MFC (Microsoft Basic Class Library)
ActiveX template class library
Other sdks, such as OpenGL, DirectX, activemove, drawdib (wing).
VC is a synthesis of many technologies, just like Shaolin 72. Generally, it is enough to learn a few in application. Our purpose now is actually just to learn a set of Shaolin Changquan. This set of long fists should include:
1. Develop strict software development habits and be familiar with the basic principles of software engineering.
2, C language foundation
3. The most basic content of 3.C+++:the concepts of class, inheritance, encapsulation and polymorphism.
4. How to use the wizard to establish the program framework.
Step 5 design the menu
Step 6 design the toolbar
7. Design and use dialog boxes, and be familiar with the most commonly used dialog box controls: buttons, static text, edit boxes, etc.
8. Know how to create new classes, member functions, member variables and message handling functions.
9. Understand the most commonly used window messages: such as WM_PAINT (repaint window), mouse down, bounce, move, initialization dialog box, etc.
10. Understand the simplest GDI (graphics device interface): write, frame, draw dots, draw lines, draw circles, set brushes, brushes.
1 1, familiar with the most commonly used MFC classes:
CWnd
document
view
Centers for Disease Control and Prevention, USA
CDialog
CWinApp
CGdiObject and its subclasses
Simple data types, such as CString, CPoint, CRect and CSize.
CFile
These contents mentioned above are all the contents that everyone will use.
Second, the introduction of MFC
The above main contents are closely related to the actual operation, so it is impossible to explain them clearly here. Moreover, it will be mentioned in these general books. I will mainly introduce the most important MFC.
MFC is the encapsulation of WindowsAPI, which greatly simplifies our work. Learning VC is mainly learning MFC. There are about 100 classes, but only twenty or thirty are commonly used. We should understand these common lessons like memorizing four words; Of course, don't learn by rote, but learn by looking for help, examples and hands-on exercises; Moreover, you don't have to learn functions in every class, but you have to accumulate over time. If you really want to be a master, it is also a good surprise method to make a notebook, write down the classes and functions you think are important and learn them at any time.
This is the most important MFC.
CWnd: Window is the parent class of most "visible objects" (almost all visible objects in Windows are a window, and there are many small windows in a large window), such as view CView, frame window CFrameWnd, toolbar CToolBar, dialog CDialog, buttons CButton, etc. One exception is that the menu (CMenu) is not derived from the window. This kind is very big. You don't have to learn it at first, just know it.
CDocument document, responsible for the interaction between memory data and disk. The most important ones are OnOpenDocument, OnSaveDocument, and Serialize.
CView view, responsible for the interaction between memory data and users. Including the display of data and the response of user operations (such as menu selection and mouse response). The most important thing is OnDraw, which usually starts with cwnd:: invalid (). In addition, it also handles menus, toolbars, shortcut keys and other user messages through the message mapping table. Many of your own functions have to be added, and you handle the most.
CDC device text. Both monitors and printers draw pictures for users to see. This picture is abstracted as CDC. CDC and other GDI (graphics device interface) complete the display of text, graphics and images. Think of CDC as a piece of paper. Every window has a CDC, which is responsible for drawing windows. CDC has a common subclass of CClientDC (window client area), and drawing is usually done through CClientDC.
Dialogue dialog box
CWinApp application class. Similar to the main function in C, it is the entrance and manager of program execution, responsible for the establishment and deletion of programs, the establishment of main windows and document templates. The most commonly used function InitInstance (): initialization.
CGdiObject and its subclasses are used to draw pictures on device text. They all need to be selected into DC before use.
CPen pen, draw lines
CBrush, fill
CFont font, the font that controls text output.
bitmap
pallette
CRgn area, which specifies the area that can be used for special processing.
CFile file. The most important thing is to open, read and write.
CString string. Encapsulating character arrays with C is very practical.
CPoint is (x, y) pair.
The correct rectangle is (left, top, right, bottom)
The size of CSize is (cx, cy) pairs (width and height).
Third, make good use of MSDN and examples.
As an improvement, the recommended examples are:
NHello's simplest program framework
Descriptable mouse drawing. Tutorial: programming basics, GDI
The simplest example of nDiblook image processing
network browser
NEnroll database
An example of nDaoviewDao (data access object). Tree view and column view controls
NCubeOpenGL example, draw a box that keeps spinning.
NHierSvrOLE server
Customer-free packaging container
NDrawcli mouse drawing. Including OLE.
Wordpad wordpad OLE
Fourth, some experience.
A. why do you want to program with Windows instead of DOS?
Windows programming is not much more difficult than DOS programming, but when I first came into contact with it, I felt very confused and didn't know where to start. In fact, if you know C language, you will find that Windows programming is not more difficult than when you learn C language. To become a master of DOS programming, you need to learn hundreds of functions (whether TC, BC, MicrosoftC) and have a deep understanding of DOS function calls at assembly language level. Now under Windows, the same workload can earn several times the income. If you used to be familiar with DOS programming and now you are engaged in Windows programming, then in just two weeks, you will definitely feel great advantages: under DOS, you have to do everything yourself, and there are restrictions such as 64K memory and display accuracy, which really get twice the result with half the effort.
B. Why use VC instead of other Windows programming languages?
N Most large-scale software (including Windows itself) is written in C and C++, so there are a lot of source codes available. For example, Photoshop has a VC programming interface. No other language has historical advantages as VC. Moreover, there are many VC development tools, from control companies to hardware developers, and few of their products dare not provide VC interfaces.
NVC is suitable for organizing large-scale projects (VB is not suitable)
NBorlandC++ or C++Builder is also very good, not worse than VC. However, the version compatibility of BC is not good, there is a "generation gap" from 3. 1 to 4.0, and VC provides extremely rich documents and examples, and VC has far more reference materials than BC. Moreover, VC and other members of VisualStudio can coordinate their work, which is beneficial to software engineering.
n
C. Don't learn WinAPI programming at first, but you'd better learn WinAPI later.
Especially don't buy books about WindowsSDK programming at first. A notorious example is "HelloWorld". Various computer languages often give an example in the introductory class, showing a line of words "HelloWorld". Whether in Basic, C, Pascal or even assembly, this simplest small program can be written in a few lines of code. However, in early Windows programming, the famous "HelloWin" example just mentioned needed to organize a project and write hundreds of lines of code. This scared away many people who wanted to learn Windows programming. In fact, the easiest way to display "Helloworld" under Windows is only five lines:
# contains "windows.h"
voidWinMain()
{
MessageBox(NULL，“HelloWorld！” ，“MyFirstWindowsApplication”，MB _ OK)；
}
Of course, this program only creates a simple dialog box, but this is enough.
Without SDK programming experience, learning VC is to use MFC to bypass many details of Windows programming. There are good tools, why not use them? Now you can write a "HelloWorld" in VC, just write one line of code.
voidCYourView::OnDraw(CDC*pDC)
{
//... Other codes
pDC->； TextOut( 100， 100，“HelloWorld！” );
}
But MFC is not omnipotent, and there are many functions in WinAPI and VC that MFC cannot embody. After getting started, WindowsAPI is still very important if you want to give full play to all the capabilities of VC. Moreover, these APIs are also available in other Windows languages.
Learning languages is similar to practicing martial arts. Windows programming languages such as VC, VB, Dlphi and VFP all belong to the same sect: Windows Gate. Although their moves are different, their internal skills are the same. This is the WindowsAPI (Application Programming Interface), with about 2000 functions. Any martial arts and moves, no matter how complicated, can usually be recorded in a very short time; But internal strength does not happen overnight. And the internal strength of different sects is different. Unix and Linux have the internal strength of Uinx, Apple has the internal strength of Mac, and Java is a school of its own. By learning VC, we mean learning moves. One month is enough to learn moves, and two weeks is enough for smart people. It's enough to scare people with moves, but fighting with masters will definitely make a fool of yourself. To master VC, you must be familiar with WindowsAPI.
D. High-level languages and natural languages
High-level languages are similar to natural languages. There are three key elements:
Grammar: It is relatively easy to understand the basic grammar of C and C++.
Rhetoric: the art and style of programming. Usually, this is related to software engineering. The trick in the algorithm is not the key. Rigidity, strict compliance with norms, and great creativity at the same time, this is the true nature of linguists.
Vocabulary: How to use other people's works? How to make use of your previous job? This is the key to the success of software engineers. If you don't have a rich vocabulary, you can't write a good article or express your thoughts. A person's grammar is basically learned before going to primary school, and his rhetorical level is determined when he is young. It's just that his vocabulary needs to be constantly studied and expanded as needed. In VC programming, a large vocabulary means mastering more programming components such as classes and functions. Such as: WindowsSDK, MFC, and ready-made SDK in your professional field, such as OpenGL in 3D programming, DirectX in multimedia programming, and Victor library in image processing. In addition, mastering ActiveX controls is often the key to success. Our work in recent years has also been summarized into a class library called IPX (Image Processing Framework), which greatly simplifies the work of image processing. However, there are still many details to be solved. If students are interested, they can take part in this work.
When learning VC, don't use the way we learn English at school, but use the way children learn to speak. The so-called method of learning English is the mode of learning C language when we were undergraduates: knowing every detail in detail, memorizing a lot of rules, rarely practicing on the computer, having no practical problems to solve, and finally judging the learning results by exams. The consequences of this model are very clear to everyone: we have studied English for more than ten years, but many people can only write articles of four or five thousand words, and they can't speak or listen; Especially terrible is that I can't understand the help documents of VC. We should learn grammar, rhetoric and vocabulary in use like babies; At first, I could only make up the worst, just like a child would only say, "dad takes a car" at first; But the words "dad" and "car" are what children need most, and the efficiency of learning is the highest. When learning VC, we should start from the demand, do the simplest first, and then become more complicated bit by bit, like snowballing.
Learning VC especially needs to communicate with others. If you think hard and don't understand, maybe someone else will have solved it long ago. Be good at learning: find useful books from bookstores; Learn from the masters around you; Find available source codes, class libraries, components, controls and libraries; If you can surf the internet, it will solve the problem even more.
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Lchrennew:
The following contents are not allowed to pass because they have been edited and replaced, so I added my version in the following way, please compare:
VC is the abbreviation of English, and its complete form basically includes the following aspects:
1. Medicine, pharmacy and biochemistry: vitamin C, abbreviated as VC, transliterated as "vitamin C", literally translated as vitamin C in Chinese, also known as ascorbic acid.
[Excerpted from /question/5925454.html]
1907 Norwegian chemist holst found it in lemon juice. Pure products are only available in 1934. It is a colorless crystal, which belongs to water-soluble vitamin, easily soluble in water, and its aqueous solution is acidic, so it is called ascorbic acid. It is stable in acidic solution and easy to be oxidized and decomposed in neutral or alkaline solution. Metal ions such as iron and copper can accelerate its oxidation rate.
The main functions of vitamin C in human body are: participating in the redox process in vivo, promoting human growth and development, enhancing human resistance to diseases, promoting the formation of collagen in intercellular substance, maintaining the normal functions of teeth, bones, blood vessels and muscles, and enhancing the detoxification ability of liver. When the human body lacks vitamin C, there will be symptoms such as bleeding gums, loose teeth, fragile bones, easy bleeding of mucous membranes and subcutaneous tissues, and difficult wound healing. In recent years, scientists have also found that vitamin C can prevent nitrite and secondary amine from combining into carcinogen-iminodiamine in the stomach, thus reducing the incidence of cancer.
2. Software, computer science and Windows development: Visual C and Visual C++ are important members of Visual Studio, which is a visual integrated development environment (IDE) developed by Microsoft. Its programming specification conforms to the ANSI C/C++ standard, and integrates the basic class library developed by Microsoft (MFC) and the visual development environment. VC provides a large number of APIs for Microsoft Windows operating system, which greatly improves the development efficiency compared with other languages. But the program written by MFC can only run under the Windows operating system.
3. In the economic and financial field, company operation: venture capitalists are also called "venture capital", which generally refers to investment in high-tech industries. As an investment field with great investment risks outside mature markets, its capital comes from financial capital, individual capital, enterprise capital, pension fund and medical insurance fund. As far as the practice of various countries is concerned, venture capital mostly operates in the form of investment funds.
Venture capital has different characteristics from general investment, as follows:
1) high risk. The object of venture capital is mainly small and medium-sized high-tech enterprises that have just started or have not yet started. The enterprise is small in scale and has no fixed assets or funds as collateral or guarantee. Because the investment target is often a "seed" technology or an idea, and they are in the initial design stage and have not been tested by the market, there are many uncertain factors whether they can be transformed into real productivity. Therefore, high risk is the essential feature of venture capital.
2) High profitability. Venture capital is a forward-looking investment strategy, and expecting high growth and high added value of enterprises is the internal driving force of its investment. Once the investment is successful, it will bring ten times or even hundreds of times the return on investment. High risk and high return are fully reflected in the process of venture capital.
3) Low liquidity. Venture capital is to invest in the early stage of the establishment of high-tech enterprises. When the enterprise is mature, it can realize the equity through the capital market, get a return, and then carry out a new round of investment operation. Therefore, the investment cycle is long, usually 4 ~ 8 years. In addition, when venture capital finally exits, if the export is not smooth, it will be very difficult to withdraw funds, which will lead to a decrease in the liquidity of venture capital.
In essence, venture capital is a support system for high-tech industries in the process of investing capital and making effective use of it. Its main functions are to accelerate the transformation of high-tech achievements, expand high-tech industries and catalyze the vigorous development of knowledge economy. Of course, for the whole national economy, venture capital is of great significance in promoting technological innovation of enterprises, promoting the adjustment of industrial institutions, changing the social employment structure, expanding the channels for individual investment choices, and strengthening the depth of the capital market.
The abbreviation of VC German Visual Components Company is very famous in the industry.
German company vision components is recognized as a leading manufacturer in smart cameras. Its camera products integrate image acquisition, processing, I/O control and communication. And the most powerful DSP is used for image processing, with high intelligence and low cost, which is an ideal choice for users to build a machine vision system.
Features of VC smart cameras:
1. The operation speed is comparable to that of PC.
2. It is convenient to connect with other equipment on the production line.
3. Video images of 3.SVGA or SXGA can be directly output on the display.
4. Provide a highly open image processing library and some common libraries.
5. Be able to carry out secondary development at the source code level.
6. The working process can be completely separated from the PC.
VC is also the abbreviation of vincent carter, a famous NBA player.