ZX Classroom - LIST #4 Cleaner: Utility for Cleaning BASIC Listings of Control Codes

LIST #4 Cleaner

BASIC program protection comes down to preventing program interruption and preventing it from being listed.

In the first case, it is enough to load the program with Multicopy, then press the V(IEW) and A(BORT) keys and save the program.

In the second case, the color codes, print coordinates, etc. need to be removed from the program. The following program does this:

10 CLEAR 29999
20 FOR F=30000TO30042
30 READ A:POKE F,A
40 NEXT F
50 PRINT #0; O.K.
60 SAVE CHR$ 240+ 4 CLE ANER CODE 30000,43
100 DATA 33,32,0,9,235,
110 DATA 9,115,35,114,237
120 DATA 183,237,82,235,
130 DATA 35,114,201,32,0,
140 DATA 13,202,244,9,
150 DATA 195,244,9

Type in the supplied listing and run it.

If everything is in order, save it to tape under the name LIST #4. The program can be loaded anywhere in memory. To use it, load a BASIC program that will not start. Then load the supplied program and run it with LOAD CODE 40000:RANDOMIZE USR 40000. List the BASIC program with LIST #4. This avoids all codes below 32.