STAR.bas for ATARI 800XE

Author: Alfonso Luis Suarez Diaz (Colombia)
Category: Christmas Challenge
System:   ATARI 800XE
Language: BASIC
Len source code: 140 bytes
Len exe file:    129 bytes
Len code only:   Not apply

Instructions:
how to run the code in an emulator
1. Download emulator from https://www.virtualdub.org/downloads/Altirra-4.01.zip
2. Unzip files in a single folder like "Altirra_4_1"
3. Run Altirra64.exe
4. In the menu. select:  System/Internal Basic (Boot without Option key)
5. In the menu. select: System/Warm Reset
6. Open star_Source.txt and copy all code text from it. (Like Ctrl-A,  Ctrl-C)
7. In the emulator screen do Right Click. then click on "Paste". Wait for all code to be writen. Hit Enter key
8. Write: RUN   then hit Enter key


Description:
The folowing code in Basic has 2 lines: Line 1 contais all logic of the program. Line 2 prints enter for each line and closes both Next loops

1 DIM T$(1):FOR Y=-8 TO 8:FOR X=-8 TO 8:B=ABS(Y):A=ABS(X):T$=" ":IF ABS(B-A)<5 AND (A<5 OR B<5) THEN T$="*"
2 PRINT T$;:NEXT X:PRINT:NEXT Y

Explanation:
DIM T$(1) 					 Declares a string variable for write either a star "*" or a space " "
FOR Y=-8 TO 8:FOR X=-8 TO 8  Creates a 17x17 2 dimentional cartesian reference using both negative and positive numbers for each axis
B=ABS(Y):A=ABS(X)			 Calcules positive coordenates for any of the 4 cuadrants
ABS(B-A)<5					 marks a diagonal of 5 pixels width
(A<5 OR B<5)				 Exclude the 4 corners
PRINT T$;					 Print either a star or a space
NEXT X:PRINT:NEXT Y			 Close each for loop and print an enter between lines

Comments:
No exe file was provided since it would be hard to load in the emulator. Copying text seemed more efficient.