Frequently Asked Questions
Q. Does Visual Logic run on a Mac?
A. Sorry, but Visual Logic only runs on Windows OS.
Q. What is a Visual Logic Signature (VLSig) file? Why do I need one?
A. The VLSig file provides a personal electronic signature to authenticate your work. Your VLSig file is created for you when you consume the PIN code that comes with your license.
You need your VLSig file to save your work. The authenticated author is saved with each solution file.
If you run Visual Logic without a VLSig file, you will be in Demo mode and you cannot save your work. (In other words, only authenticated work can be saved.)
Q. I entered my PIN code but I did not get the email with my VLSig file. What should I do?
A. Some mail servers mark files with unknown attachments as spam and put it into another folder. If you have a spam folder, look there. Regardless, as a delivery backup, you can download your VLSig file directly from the page http://www.visuallogic.org/course/downloadvlsig.html
Q. I have my VLSig file. What do I do with it?
A. Save your VLSig file to a safe place. When you run Visual Logic, you will be asked to browse to your VLSig file. (If you need Visual Logic, you can download it by clicking on http://www.visuallogic.org/course/VisualLogic-Course.exe.) Note: If you happen to have a USB thumb drive, you can save both the Visual Logic executable and your VLSig file on the thumb drive and then you can run Visual Logic directly from the thumb drive.
Q. Can I drag-and-drop my flowchart elements?
A. Yes, you can change the position of a single element or multiple selected elements using the mouse. You can also cut/copy/paste selected elements using CTRL-X, CTRL-C, and CTRL-V.
Q. When exporting my Visual Logic program to Visual Basic .NET, it does not run. What's wrong?
A. You may have to rebuild the VB.NET solution before it will execute on a .NET Framework machine.
Q. How does Visual Logic handle data types?
A. To keep syntax at a minimum, Visual Logic treats all data as Variants, and usage of a variable is determined by its context.
Q. Is Visual Logic case-sensitive?
A. No. Students are recommended to distinguish variables by unique and descriptive names, not by varying the case.
Q. Does Visual Logic support operator precedence?
A. Yes. Visual Logic follows standard operator precedence, working from the innermost set of paretheses first:
Mulitplication (*) and Division (/)
Integer Division (\)
Integer Remainder (MOD)
Addition (+) and Subtraction (-)
Q. Does Visual Logic support logical operators?
A. Yes. The AND, OR, XOR, and NOT operators can be used to create compound conditions. In Visual Logic (or any programming language) we recommend that compound conditions use parentheses to explicitly denote each condition. This recommendation is based both on the emphasis of clarity, and the realities of multiple levels of operator precedence. This is especially important for a non-strictly typed language such as Visual Logic.
Example: Create an Output statement with the following expression: (4 > 3) AND (3 > 2)
With parentheses the expression is unambiguous and will evaluate as you expect it to (e.g., TRUE). If you remove the parentheses, the condition may evaluate in an unexpected or undesirable way.
Q. What Intrisic Functions are supported by Visual Logic?
A. Here are some of the more common Intrinsic Functions in Visual Logic:
|Random(5)||A random number between 0 and 4|
|Random(100) + 1||A random number between 1 and 100|
Q. How do I step through programs in Visual Logic?
A. Visual Logic stepping is modeled after Visual Studio, so F8 steps into programs and procedures.
Q. Does Visual Logic support Text File I/O?
A. Yes. To do text file I/O, double-click on the Input (or Output) element to show the edit dialog, click "More >>", and select the File option button, and then specify the appropriate text file name.
Steps for creating an input text file:
To create an input file, you should use Notepad or a similar tool to create a simple .txt file. When reading input from a file, each line in the file is like one entry in console mode. You should therefore keep the input file to one input item per line. (And be sure to include quotes around string input, just like with console or dialog input.)
Four tips to remember when doing file I/O:
- First, do NOT use quotes around the text file name in the I/O dialog.
- Second, DO use quotes around string data inside the text file. (Note that File input works the same as Console input in that strings must have delimiting quotes, and that the delimeters can be either single or double quotes, just so long as you use the same delimeter to start and stop the string.)
- Third, if you use a relative reference (without the full path name), make sure the file is in the same folder as the Visual Logic .exe executable (which is not necessarily the same as the *.vls solution file).
- Fourth, if you have both FileInput and FileOutput in the same program, you must use different filenames for the Input and Output files.
Q. Can I print the flowchart?
A. Yes. From the main menu, select "View|Create Flowchart Metafile" to save the image. You can then embed the image into a Word (or Powerpoint!) document and print it.
Q. Does Visual Logic handle arrays?
A. Visual Logic does handle arrays. It also handles procedures, parameters (ByVal and ByRef), and text file I/O.
Q. How do I watch a variable? step by step?
A. When you Step Into (F8), a Variable Watch window automatically appears.
Q. What else can I do with Visual Logic other than run a simple program?
A. Visual Logic can do it all... variables, input, assignment, output, conditions, loops, procedures, arrays, files, graphics, debugging, variable watch... everything an instructor needs to teach programming logic and design.
Q. When I run the program, I get an error message "Problem shutting down Executor!" What should I do?
A. The previous simulation is still running in the background. Select the menu option Debug | Terminate, and that will kill the prior simuation, and you are ready to go.