5 ! THIS PROGRAM WAS WRITTEN BY DON PENLAND
6 ! SURPRISE VALLEY HIGH SCHOOL, CEDARVILLE  CA  96104
10 DIM A(20)
20 ?:?
30 ? "THIS PROGRAM WILL FIND THE GREATEST COMMON FACTOR OF UP TO "
40 ? "TWENTY NUMBERS."
50 ?:?
60 INPUT "HOW MANY NUMBERS WILL YOU BE USING ";M
70 IF M>20 THEN PRINT "ONLY UP TO 20 NUMBERS.":GOTO 60
80 FOR I=1 TO M
90 ? "NUMBER ";I;
100 INPUT A(I)
110 NEXT I
120 L=99999
130 FOR I=1 TO M
140 IF L<A(I) THEN 160
150 L=A(I)
160 NEXT I
170 FOR C=L TO 1 STEP -1
175 IF C=1 THEN 280
180 FOR I=1 TO M
190 IF A(I)/C<>INT(A(I)/C) THEN 270
200 NEXT I
205 ?:?
210 ? "THE GREATEST COMMON FACTOR FOR ";
220 FOR I=1 TO M
230 ? A(I);
240 NEXT I
250 ? " IS ";C
260 GOTO 340 
270 NEXT C
275 ?:?
280 ? "THE NUMBERS ";
290 FOR I=1 TO M
300 ? A(I);
310 NEXT I
320 ? "HAVE NO GREATEST COMMON FACTORS."
330 ?:?
340 ? "DO YOU WANT TO FIND ANOTHER GCF? ";
350 INPUT A$
360 IF A$="YES" OR A$="Y" THEN 50
370 ? "BYE FOR NOW.  IT'S BEEN FUN WORKING WITH YOU."
999 CHAIN "MATH2"
1000 END