vb.net barcode scan event Some Programming Constructs in Software

Draw QR Code JIS X 0510 in Software Some Programming Constructs

5.2 Some Programming Constructs
QR Code 2d Barcode Reader In None
Using Barcode Control SDK for Software Control to generate, create, read, scan barcode image in Software applications.
Paint QR Code JIS X 0510 In None
Using Barcode drawer for Software Control to generate, create Quick Response Code image in Software applications.
In this chapter we use some more programming principles. The following explains these principles to allow for easier comprehension of the programs that will be developed.
Recognizing QR Code ISO/IEC18004 In None
Using Barcode recognizer for Software Control to read, scan read, scan image in Software applications.
QR Creation In Visual C#
Using Barcode drawer for .NET framework Control to generate, create QR Code image in .NET applications.
RANDOM ROAMING
Painting QR Code 2d Barcode In Visual Studio .NET
Using Barcode printer for ASP.NET Control to generate, create Denso QR Bar Code image in ASP.NET applications.
QR Code JIS X 0510 Generation In .NET
Using Barcode printer for .NET framework Control to generate, create QR image in .NET applications.
5.2.1 LABELS AND SUBROUTINES The next program we will develop will be divided into sections. Each section will achieve a speci c task. The main program will call each section as it becomes needed. This principle is a powerful strategy; divide a complex task into a set of simpler tasks. Each simpler task can also be divided further. This process makes it easier to complete the project as a series of simple tasks that can be easily accomplished. Some tasks may have been previously accomplished in other projects and can be used again in the current project with only minor modi cations. Also you can assign different people to work on each subtask; this way a large project can be nished in less time than if one person was working on it. The main program acts as a manager program calling the subtasks as they become needed. An example program organized in this manner is shown in Fig. 5.2. In RobotBASIC you can achieve this kind of structure with subroutines. Think of a subroutine as a tool that you use to do a certain task. Usually when you use a tool you do not care how it accomplishes its work as long as you know how to use it. To achieve a big project you will use many tools together. You come to a point where you need the tool, so you pick it up and use it. When you nish you put it down and proceed (maybe use another tool). When a project becomes too complex you can summon the aide of specialists and divide the overall project among these specialists who then use tools to do their work. The specialists may utilize additional specialists and so on. This is exactly how programs should be developed. Programs should have a main routine that calls on subroutines that act as tools or specialists. In RobotBASIC a subroutine is marked as such by surrounding some lines of code with a Label and a Return statement (see Fig. 5.2). The label is the name of the subroutine. A label has to start with a letter followed by any combination of letters and numbers and has to end with a colon (:) (see Secs. B.5 and C.1). As you can see in Fig. 5.2 we have the labels Task_1 and Task_2, which are markers for subroutines surrounded by the label and the command Return.
QR Code ISO/IEC18004 Creator In Visual Basic .NET
Using Barcode generator for VS .NET Control to generate, create QR-Code image in .NET applications.
Painting EAN-13 In None
Using Barcode encoder for Software Control to generate, create GTIN - 13 image in Software applications.
MainProgram: //--setup some initial stuff here //--do the various tasks gosub Task_1 gosub Task_2 //Etc. Etc. //--do some closing up stuff here End //--this is needed to stop the program //---------Task_1: //do stuff here Return //---------Task_2: //do stuff here Return //---------//Etc. etc.
Barcode Creation In None
Using Barcode drawer for Software Control to generate, create barcode image in Software applications.
Creating Barcode In None
Using Barcode maker for Software Control to generate, create barcode image in Software applications.
FIGURE 5.2 Well structured program.
Generating Code 39 Full ASCII In None
Using Barcode maker for Software Control to generate, create Code 39 Full ASCII image in Software applications.
DataMatrix Generation In None
Using Barcode generator for Software Control to generate, create Data Matrix 2d barcode image in Software applications.
BUILDING BLOCKS
Identcode Creator In None
Using Barcode encoder for Software Control to generate, create Identcode image in Software applications.
Read Bar Code In Java
Using Barcode scanner for Java Control to read, scan read, scan image in Java applications.
NOTE:
Generate Linear In Visual C#
Using Barcode encoder for .NET Control to generate, create Linear image in .NET framework applications.
Scanning Code 39 Extended In Java
Using Barcode recognizer for Java Control to read, scan read, scan image in Java applications.
Labels are case sensitive, so Task:, TASK:, and task: are not the same. RobotBASIC is generally not case sensitive. Variable names, array names, and labels are the exceptions to this rule.
Code 128 Code Set A Recognizer In C#.NET
Using Barcode scanner for VS .NET Control to read, scan read, scan image in VS .NET applications.
Scanning UPC - 13 In VS .NET
Using Barcode decoder for VS .NET Control to read, scan read, scan image in VS .NET applications.
You invoke a subroutine (use the tool) by using the command Gosub followed by the name of the subroutine which is the label that you have given it (without the colon [:] ) such as Gosub Task_1. Once the program issues this statement it will jump to the label and start executing the subroutine from that label until it encounters the command Return. The Return command ends the subroutine and causes the program ow to go back to the line immediately following the line where the subroutine was called. See Secs. B.5, B.6, C.1, and C.6 for more details on ow-control structures.
Bar Code Encoder In Objective-C
Using Barcode drawer for iPad Control to generate, create bar code image in iPad applications.
Drawing Data Matrix 2d Barcode In .NET
Using Barcode generator for ASP.NET Control to generate, create DataMatrix image in ASP.NET applications.
NOTE:
The End statement is necessary to stop the program from continuing on to the area of the subroutines.
The more you program the more you will nd that you may have already designed a routine in some previous project to achieve what you are trying to do in the current project. If you have designed the routine as a subroutine, then all you have to do in the current project is cut and paste the previously created routine. As your toolbox of routines becomes more extensive, you will nd that you can develop programs more quickly and more easily. You will see how all this applies in practice with the program we will develop in the next section for testing various random roaming algorithms. 5.2.2 COMMANDS RobotBASIC has commands to accomplish many tasks. You have seen in Chap. 4 that there are commands to perform I/O (input and output) with the user. In this chapter you will use commands to do various actions on the screen. There are commands to clear the screen (ClearScr), set the color for drawing on the screen (SetColor), position the initial point to start drawing (GotoXY), to draw lines on the screen (LineTo), and to set the width of the lines being drawn (LineWidth). RobotBASIC has a multitude of commands to help you deal with many different types of programming situations. See Secs. B.4, C.7, and C.10. Remember, commands are not case sensitive. 5.2.3 OPERATORS Operators are symbols that operate on numbers or strings. There are math operators to do things like add ( ) and multiply (*). There are comparison (or relational) operators to see if two things are equal ( ) or if one thing is less than another ( ). There are logical operators that enable you to test if some condition is true AND another is true, or if another condition is true OR another is true. There are bitwise operators that will operate on the individual bits of a number (binary e.g., bAnd).
NOTE:
Copyright © OnBarcode.com . All rights reserved.