Principles and Concepts I

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Principles and Concepts I

• G- Code Learning Group (3)
• Jonathan Remo
• Mayank Srivastava
• Zhigang Wang

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Overview

• History of Computer Programming Languages.
• Visual Basic Concepts
• Application of Visual Basic

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• What is a Program?
• Program is a specific set of ordered operations
  for a computer to perform.

• What is a Complier ?
• A special program that processes statements
  written in a particular programming
• language and turns them into machine language
  or "code" that a computer's
• processor uses.

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Charles Babbages Difference Engine

• The earliest form of a computer language was
  physical motion.
• The tasks were executed by changing the gears
  which performed the calculations.

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Electronic Numerical Integrator (ENIAC)

• Calculations were performed using electrical
  signals in stead of physical motion.
• "Programmed" by presetting switches and rewiring
  the entire system for each new "program" or
  calculation.

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John Von Neumann

• Shared-program technique
• Conditional control transfer
• Conditional control transfer the brought about
  the idea computer code should be able to branch
  based on logical statements such as IF
  (expression) THEN, and looped such as with a FOR
  statement.
• Conditional control transfer also gave rise to
  the idea of libraries.

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Short Code

• Short Code was the first computer language for
  electronic devices.
• Required the programmer to change its statements
  into 0's and 1's by hand.

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Grace Hooper and the Complier

• A compiler is a program that turns the language's
  statements into 0's and 1's for the computer to
  understand.
• Lead to faster programming

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Auto Code

• The AutoCode-compiler, which compiles symbolic
  assembler language on a Manchester Mark I
  computer.

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Fortran

• The first of the major languages.
• Developed by IBM for scientific computing.
• Language included IF, DO, and GOTO statements.
• The basic types of data in use today got their
  start in FORTRAN, these included logical
  variables (TRUE or FALSE), and integer, real, and
  double-precision numbers.

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LISP

• Designed for Artificial Intelligence (AI)
  research.
• The difference between this language and other
  languages is that the basic and only type of data
  is the list, denoted by a sequence of items
  enclosed by parentheses.
• LISP programs themselves are written as a set of
  lists, so that LISP has the unique ability to
  modify itself, and hence grow on its own.

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AlgolAlgorithmic Language

• Independent of specific type of hardware.
• Language was carefully and formally designed.
• Algols major contribution is being the basis for
  Pascal, C, C, and Java.
• It was also the first language with a formal
  grammar, known as Backus-Naar Form or BNF.

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COmmon Business Oriented Language (COBOL)

• Designed from the ground up as the language for
  businessmen.
• Data types were numbers and strings of text.
• It allowed for the data to be grouped into arrays
  and records, so that data could be tracked and
  organized better.

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BASIC (Beginners' All-purpose Symbolic
Instruction Code)

• John Kemeny and Thomas Kurtz invents BASIC and
  its compiler. It was developed at Dartmouth
  College as a teaching tool

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Pascal

• Pascal was developed mainly out of necessity for
  a good teaching tool.
• Designed in a very orderly approach, it combined
  many of the best features of the languages in use
  at the time, COBOL, FORTRAN, and ALGOL.
• The combination of features, input/output and
  solid mathematical features, made it a highly
  successful language.
• Pascal also improved the "pointer" data type, a
  very powerful feature of any language that
  implements it.
• It also added a CASE statement that allowed
  instructions.

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C

• C was developed the Unix system. Unix gives C
  such advanced features as dynamic variables (e.g.
  variant), multitasking, interrupt handling,
  forking, and strong, low-level, input-output.
• Because of this, C is very commonly used to
  program operating systems such as Unix, Windows,
  the MacOS, and Linux.

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OOP and C

• In the late 1970's and early 1980's, Object
  Oriented Programming, or OOP was developed.
• Objects are pieces of data that can be packaged
  and manipulated by the programmer.
• In 1983 developed into the language C
•  C was designed to organize the raw power of C
  using OOP, maintain the speed of C and be able to
  run on many different types of computers.

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Visual Basic (VB)

• Evolved from BASIC
• With the development of Microsoft windows
  graphical user interface (GUI) in the late 1980s
  and the early 1990s, BASIC evolved into VB.
• VB is developed on using forms and windows using
  in which a programs drags and drops into the
  program.

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JAVA

• Netscape licensed Java for use in their internet
  browser.
• Has optimization problems
• Java may wind up as the instructional language of
  tomorrow as it is truly object-oriented and
  implements advanced techniques such as true
  portability of code and garbage collection.

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Visual Basic Concepts

• VB is windows based programming language that
  allows a programmer to build applications running
  under Windows.
• VB constructs the necessary building blocks that
  a Windows application needs
• Hence, very little coding needs to be performed
• Integrated development environment (IDE) allows
  the programmer to create, run and debug Windows
  programs in one application
• VB is a EVENT driven language
• Code is written to respond to specific events
• Allows code to be short and is compartmentalized
  by events.

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Visual Basic Environment

• How to start Visual Basic?

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Visual Basic Environment

• Integrated Environment Screen
• Menu Bar lists of commands
• Tool Bar quick access to mostly common used
  objects
• Formwindow where the application is designed
• Project Explorer a list of forms,modules,
  classes or ActiveX components
• Properties Window a list of the property
  settings for a control
• Tool Box a set of tools designing applications
• Form Layout set the forms screen position

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Menu Bar Tool Bar Project Explorer Prope
rties Window Layout Form
Toolbox Form
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Picture Box Text Box Command Button Option
Button List Box Vertical Scroll Bar Drive
Box File list Lines Data Control
Selection Tool
Label
Frame
Check Box
Combo Box Horizontal Scroll Bar Timer Directory
List Shapes Image Box OLE Control
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Operations on a Project

• How to Open?
• Choose the file open icon on the toolbar or the
  file open menu
• Type in or choose the name of the file to open
• Same as other MS software

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Operations on a Project

• How to Save?
• A VB project consists of many forms, modules, and
  graphics, and all of them are saved within
  separate files within the project
• Project File Extensions
• Design-time Files
• Miscellaneous Development Files
• Run-time Files
• Saving a project
• Saving a form or module
• Automatic saving of project files and forms
• Using help

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Using Controls on a Form

• Adding a control to a form
• Selecting a control
• Resizing a control
• Deleting a control
• Moving a control
• Setting control properties
• Object Box displays the name of the selected
  control
• Properties List displays a scrollable list of
  all properties for the selected control
• Adding code to controls
• Option Explicit error preventing statement

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Adding Comments to Code

• Comments are useful to remind the programmer
  about the purpose of the code or any problems
  with it
• Text within the code window are color coded
• Green comments
• Blue valid VB commands
• Black programmers code

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Building A Visual Basic Application

• Step 1 Draw the interface
• Step 2 Set properties
• Step 3 Write codes
• Step 4 Execute the program

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Controlling the Program Flow

• Conditional Operator
• Operator Meaning
• Equal to
• gt More than
• lt Less Than
• gt More than and
  equal
• lt Less than and
  equal
• ltgt Not Equal to

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Controlling the Program Flow

• Logical Operators
• Operator Meaning
• And Both sides must be true
• Or One side or other must be
  true
• Xor One side or other must be
  true but not both
• Not Negates truth

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Controlling the Program Flow

• If Then - Else statement
• If  conditions Then VB expressions
• Else
• VB expressions
• End If
• Case Select Statement
• Select Case expression
• Case value1         Block of one or more
  VB statements    Case value2         Block of
  one or more VB Statements

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Declaring a Variable

• Dim Variable as Variable Type
• Dim r as Integer
• Dim pi as Double
• If variable is not declared the program will
  consider it as an variant

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VB Codes

• Program for finding the volume of a cone and
  a cylinder
• Dim r as double
• Dim h as double
• Dim pi as double
• Dim v as double
• r Val(radius.Text)
• h Val(hght.Text)
• Pi 22 / 7
• v Pi (r 2) h
• volume.Text Str(v)

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Functions

• The general format of a function is
• FunctionName(arguments) 
• where arguments are values that are passed on
  to the functions

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Visual Basic Applications

• Examples

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Problem Statement

• Calculate the commission
• Sales Volume() Commissions
• lt500 3
• lt1000 6
• lt2000 9
• lt5000 12
• gt5000 15

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Macro in Excel

• Function Comm(Sales_V  As Variant) as Variant If
  Sales_V lt500 Then CommSales_V0.03 Elseif
  Sales_Vgt500 and Sales_Vlt1000 Then
  CommSales_V0.06 Elseif Sales_Vgt1000 and
  Sales_Vlt2000 Then CommSales_V0.09 Elseif
  Sales_Vgt200 and Sales_Vlt5000 Then
  CommSales_V0.12 Elseif Sales_Vgt5000  Then
  CommSales_V0.15 End If End Function