14 August 2016

BBC BASIC required several changes. This BASIC has a MODulus function, array indices are 1-based instead of 0-based, and the way the Applesoft reference version jumps in and out of the inner FOR loop causes the BBC BASIC stack to be exhausted after a couple iterations. So this version uses REPEAT/UNTIL.

   10 DIM primes(100)
   20 index=1
   30 count=2
   40 found=1
   50 primes(index)=count
   60 PRINT primes(index)
   70 REPEAT
   80 count=count+1
   90 REPEAT
  100 v=(count MOD primes(index))
  110 index=index+1
  120 UNTIL v=0 OR index>found
  130 IF v=0 THEN GOTO 170
  140 PRINT count
  150 primes(index)=count
  160 found=found+1
  170 index=1
  180 UNTIL found=100