IBM PC & PCjr Magazine Correction
There seems to be an error printed in the PCjr version of David J. Bohlke's "Cannonball" game, which ran in the August 1984 issue of COMPUTE!'s PC & PCjr magazine. The program ran perfectly until I blew up RED's cannon, but all I got for an explosion was a line across the screen, then the program crashed. The error was in line 625, which reads:
625 W = INT (RND*4 + 4) : W, 15, 3 : FOR J = 1 TO 10 : NEXT
I think it should read:
625 W = INT (RND*4 + 4) : W = 15*3 : FOR J = 1 TO 10 : NEXT
It took quite a while to figure out, but I just had to experiment with the program.
Since subscribers of COMPUTE!'s PC & PCjr magazine now receive COMPUTE!, we're publishing the answer here in "Readers' Feedback." The correction you've given will prevent the game from crashing, but the line should read:
625 W = INT (RND*4 + 4 ) : SOUND W, 15, 3 : FOR J = 1 TO 10 : NEXT
We fully tested the program on a PCjr, but we made the listing for the PCjr version of the game on an IBM PC. The PCjr's SOUND command is not compatible with the PC's SOUND command, so the command itself would not list on the PC. Our staff have been alerted to watch for this potential problem in the future.