Microsoft Visual Basic WHAT IS IT? Visual Basic is a programming language developed by Microsoft for Cooper Ala. The programming language is a dialect of BASIC, with important additions. Its first version was presented in 1991 with the intention to simplify programming by using a fully graphical development environment to facilitate the creation of graphical interfaces and to some extent the same programming. Since 2001 Microsoft has proposed to abandon the development based on Win32 API and go to work on a common framework or library independent of the version of the operating system. NET Framework, using Visual Basic. NET (and other languages as C Sharp (C #) code for easy transition between them) has some serious incompatibilities with the existing Visual Basic code. Visual Basic is an IDE (integrated development environment or in English Integrated Development Environment) that has been packaged as an application program, ie, consists of a code editor (where you type in the program source code), a debugger (program correcting errors in the source code that can be either compiled), a compiler (the program that translates source code to machine language) and a GUI builder or GUI (a form of programming in which it is not necessary write the code for the graphics program, but it can be done visually).

General Characteristics It is easy to learn a language designed for both beginners and expert programmers, driven by events, and working on a forms engine that facilitates the rapid development of graphics applications. Syntax, derived from the old BASIC, has been expanded over time to add the typical characteristics of modern structured language. It has added a limited implementation of object-oriented programming (forms and controls themselves are objects), although it supports polymorphism through the use of interfaces, does not support inheritance. Does not require handling of pointers and has a very simple handling of character strings. It has several libraries for database management, and can connect to any database through ODBC (Informix, DBase, Access, MySQL, SQL Server, PostgreSQL, etc.) using ADO. It is used mainly for business management applications, due to the speed with which is a program that uses a simple database, in addition to the abundance of programmers in this language. The Microsoft compiler generates executables that require a DLL to function, sometimes called MSVBVMxy.DLL (acronym for "Microsoft Visual Basic Virtual Machine xy ', xy being the version) and other VBRUNXXX.DLL (" Visual Basic

Runtime X . XX "), which provides all the functions implemented in the language. There are also a large number of libraries (DLLs) that provide access to many features of the operating system and integration with other applications. However this is only a limitation on obsolete systems, and the libraries necessary to run Visual Basic programs come standard on all versions of Windows since Windows 2000.

Versions

Versions of Visual Basic for Windows are well known, but there is a version of Microsoft Visual Basic for MS-DOS 1.0 (Standard and Professional editions) and less widespread dating from 1992. It was an environment that, while in text mode, includes a forms designer that could drag and drop different controls. The latest version only for 16-bit, 3.0, and included a detailed library of components for all sorts of uses. During the transition from Windows 3.11 to Windows 95, version 4.0 appeared, which could lead to programs 16 and 32 bits from the same source, at the expense of a large increase in the size of the runtime required. In addition, the controls are replaced by new VBX OCX. With version 5.0, was implemented for the first time the possibility of compiling to native code, obtaining a considerable improvement in performance. Both this and the subsequent 6.0 supported features of object-oriented languages, although it lacks some important items such as inheritance, polymorphism and overloading. Version 6.0 continues to be used en masse. Current versions of Visual Basic is based on. NET platform, which is moving away from previous versions.

Advantages • It is a RAD language. • Has a learning curve very quickly. • Integrates design and implementation of Windows Forms. • Allows you to easily use the platform of Windows systems. • The code in Visual Basic is easy to Migrate to other languages. Disadvantages • Without support from Microsoft on April 4, 2008 (The MSDN is very full). • No cross-platform (however you can use emulators and interpreters to run on other platforms). • By default allows programming without a declaration of variables. (which can be corrected simply by typing the words Option Explicit in the header of each form, in which case it will be necessary to declare all variables used, which ultimately generates more pure code). • It allows low-level programming or embedded sections of code in ASM. • Only allow the use of functions from dynamic libraries (DLL) stdcall.

• Some functions are undocumented (But this happens in many languages). • It is a language based on objects and not object oriented. • Do not drive too well the memory pointers. • Does not support treatment processes as part of language. • Does not include travel operators as part of bits of language. • Do not allow dynamic memory management, pointers, etc.. as part of language. • No warning of certain errors or warnings (you can configure the compiler to generate executables without drivers integers overflow checks or limits on matrices among others, leaving more of the hands of the programmer the task of controlling these errors) • You do not have instructions for pre-processing. • The treatment is a basic Windows messages and indirect. • The range of controls are included, however in some cases, very general, which leads to having to reschedule a need for new controls specific to the application. This changed radically in Visual Basic. NET where you can reprogram and reuse or improve the existing controls. • The custom controls do not improve the power of the Windows API, and in some cases it will go to the only way to achieve the desired custom control. Development environments There is a single development environment for Visual Basic, developed by Microsoft: • Microsoft Visual Basic for X.0 versions from 1.0 to 6.0 (with the differences between the versions from 1.0 (MS-DOS/Windows 3.1) to 3.0 (16-bit Windows 3.1) and of 4.0 ( 16/32 bit, Windows 3.1/95/NT) to 6.0 (32-bit Windows 9x/Me/NT/2000/XP/Vista) Gambas is a free project for GNU / Linux inherits largely from Visual Basic language and development environment.

WHAT IS PDF? PDF is a document storage format developed by Adobe Systems. This format is a composite (vector image, bitmap and text). It is specially designed for documents that could be printed, since all the information necessary for the final presentation of the document, identifying all the details of how it's going to be, not requiring adjustment of previous processes and layout. Is increasingly being used as specification viewing, thanks to the high quality of the sources used and the facilities for the handling of the document, such as search, hyperlinks, etc..

Features

• It is multiplatform, it may be presented by the major operating systems (Windows, Unix / Linux or Mac), without modifying either the structure or appearance of the original document. • You can integrate any combination of text, graphics, pictures and even music. • One of the most common formats for the exchange of documents. So it is widely used by businesses, governments and educational institutions. • It is an open specification for which they have created free software tools that allow you to create, view or modify documents in PDF format. One example is the office suite OpenOffice.org and LaTeX word processor. • can be put to protect their content and even digitally sign it. • The PDF file can be created from multiple applications by exporting the file, such as OpenOffice.org and programs can also do with Service Pack 2 (SP2) of Office 2007 Microsoft Office Suite, Microsoft announced to release for some time of the first half of 2009.1 • It is the ISO standard (ISO 19005-1:2005) files to containers of electronic documents with a view to preserving long duración.2

History PDF files with applications that could see and create such documents, began to develop after 1991 and their adoption and general business was very small. His software was distributed as a commercial software license. At that time the PDF document viewer available free of charge but not free. Earlier versions of PDF documents did not have external links, which is why Internet adoption was substantially reduced and did not have much popularity. In those days, were common connections to the Internet via telephone modem, and the size of PDF documents is much larger than other types of documents, such as plain text (unformatted), for example, so the Broadband was a key factor for acceptance on the Internet. Moreover, since there were other types of documents that made it tough competition for the type of PDF documents, including documents "PostScript (. Ps), which in those days, they were significantly common. Over time, the PDF documents were gaining popularity in various different ways, such as advertising. Such documents started to become popular considerably, to become a standard. [Citation needed] This type of document is seen as a digital page that is ready to print exactly as shown on the screen without problems to the margins of print, as in other digital documents. In recent years its popularity, many applications have come from reading these files. His popularity has opened the possibility to create PDF documents with free software programs, as does the current OpenOffice.org. Other applications are even able to edit them, without using the typical application to create and edit documents in Adobe PDF.

The PDF file format has changed several times as new versions of Adobe Acrobat have been released. There have been nine versions of PDF: • (1993) - PDF 1.0 / Acrobat 1.0 • (1994) - PDF 1.1 / Acrobat 2.0 • (1996) - PDF 1.2 / Acrobat 3.0 • (1999) - PDF 1.3 / Acrobat 4.0 • (2001) - PDF 1.4 / Acrobat 5.0 • (2003) - PDF 1.5 / Acrobat 6.0 • (2005) - PDF 1.6 / Acrobat 7.0 • (2006) - PDF 1.7 / Acrobat 8.0 • (2008) - PDF 1.7, Adobe Extension Level 3 / Acrobat 9.0