Put it in the same folder as your GW-BASIC program. Load it and run it.

10 'List primes between two selected numbers 20 CLEAR :CLS :KEY OFF 30 PRINT "List primes between two selected numbers." :PRINT 40 INPUT "Input smaller number ";SMALL 50 INPUT "Input larger number ";LARGE 60 IF LARGE < SMALL THEN SWAP LARGE,SMALL 'Swap if entered in wrong order 70 SMALL=INT(SMALL/2)*2+1 'Ensure small number is odd 80 LARGE=INT(LARGE/2)*2-1 'Ensure large number is odd 90 FOR K=SMALL TO LARGE STEP 2 100 X=SQR(K) 'Only need to check to square root 110 F=0 'Count factors as a logic step 120 FOR J=3 TO X STEP 2 130 IF K/J-INT(K/J)=0 THEN LET F=F+1 'Totals up factors. F=0 is prime 140 NEXT J 150 IF F=0 THEN PRINT USING "########";K; 'Prime has no factors 160 NEXT K 170 END |