Introduction to VISUAL BASIC 6

The Concept of Computer Programing

Before we begin Visual Basic 6 programming, let us understand some basic concepts of programming. According to Webopedia, a computer program is an organized list of instructions that, when executed, causes the computer to behave in a predetermined manner. Without programs, computers are useless. Therefore, programming means designing or creating a set of instructions to ask the computer to carry out certain jobs which normally are very much faster than human beings can do.

Many people think that computer is very intelligent, but in actual fact it is dumb and can't do anything without human assistance. The microchips of  a CPU can only understand two distinct electrical states, namely, the on and off states, or 0 and 1 in the binary system. So, the CPU only understands a combinations of 0 and 1 code, a language which we called machine language. Machine language is extremely difficult to learn and it is not for us to master it easily.

Fortunately , we have many smart programmers who wrote interpreters and compilers that can translate human language-like programs such as BASIC into machine language so that the computer can carry out the instructions entered by the users. Machine language  is known as the primitive language while Interpreters and compilers like Visual Basic are called high-level language. Some of the high level computer languages beside Visual Basic are  Fortran, Cobol, Java, C, C++, Turbo Pascal,flash action script, JavaScript, HTML and more. 

What is VISUAL BASIC

VISUAL BASIC is a high level programming language which  evolved from the earlier DOS version called BASIC. BASIC means Beginners' All-purpose SymbolicInstruction Code. It is a relatively easy programming language to learn. The code looks a lot  like English Language. Different software companies produced different versions of BASIC, such as Microsoft QBASIC, QUICKBASIC, GWBASIC ,IBM BASICA and so on. However, people prefer to use Microsoft Visual Basic today, as it is a well developed programming language and supporting resources are available everywhere. Now, there are many versions of VB exist in the market, the most popular one and still widely used by many VB programmers is none other than Visual Basic 6 . We also have VB.net, Visual Basic 2005, Visual Basic 2008 and the latest Visual Basic 2010 . Both Vb2008 and VB2010 are fully object oriented programming (OOP) languages.

VISUAL BASIC is a VISUAL and  events driven Programming Language. These are the main divergence from the old BASIC. In BASIC, programming is done in a text-only environment and the program is executed sequentially. In VB, programming is done in a graphical environment. In the old BASIC, you have to write program code for each graphical object you wish to display it on screen, including its position and its color. However, In VB , you just need to drag and drop any graphical object anywhere on the form, and you can change its color any time using the properties window.

On the other hand, because  the user may click on a certain object randomly, so each object has to be programmed independently to be able to response to those actions (events). Therefore, a VB Program is made up of many subprograms, each has its own program code, and each can be executed independently and at the same time each can be linked together in one way or another.