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                      Open-Source BASIC Programs

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A GWBASIC compiler is included for the SPACEFIL and STATEPRK programs with this suite of software. Since source codes are provided alongside executable codes, we are including here some instructions on the compilers used to turn a source code into an executable code. Here we are a few words on GWBASIC.



GWBASIC was bundled with MS-DOS operating systems on IBM PC compatibles by 

Microsoft. It has been replaced with the release of MS-DOS 5.0. For those who want to further develop the source codes for SPACEFIL and STATEPRK, they can consider these upgraded compilers. Please note that beyond the GWBASIC compiler provided here, other free downloads are available by searching the Internet.



Some GWBASIC Commands

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GWBASIC runs on a principle of sequential commands.  Line 10 will run before 

line 20, line 20 will run before line 21, etc.  The following explains the 

most common commands:



LOAD"  :  This command will load in a file (either in ASCII text or BASIC 

programs with .BAS extension).  The file to be loaded must be inserted 

between the two " marks.  For example, if you wanted to load in the Park2.was 

file, you would type in LOAD"PARK2.WAS"



SAVE" :  Works in the same way as LOAD but saves your work as that filename 

instead.  For example, if you loaded in PARK2.WAS and wanted to save your 

work  in a file called MODIFED2.WAS, you would type in SAVE"MODIFED2.WAS"  

NOTE THAT GWBASIC WILL SAVE ALL FILES IN A MACHINE LANGUAGE FORMAT.



RUN : Type in RUN and press return to run your program.  If there are errors, 

the program will not run and tell you where the error is (the line number).



LIST : Views all command lines.



LIST X-Y : Views the command lines between the numbers X and Y (you choose 

the x and y values)  For example, to view lines 50 through 200, type in LIST 

50-200



NEW : Clears all currently entered command lines.  Use with caution!



CLS : Clears screen



SYSTEM :  This will put you back to the DOS prompt (i.e., it quits GWBASIC).



Other Useful Features

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To clear a single command line, enter the line number and press return.



To enter a new or modify a current command line, go to (or enter) the 

particular line, make changes, and press return when done.



To print output, change all PRINT statements to LPRINT statements.



To print command lines, type LLIST.

