Appendix D: Example programs
This appendix contains some example programs.
The first of these programs requires a date to be input and gives the day of the week which corresponds to this date.
10 REM convert date to day 20 DIM d$(7,6): REM days of week 30 FOR n=1 TO 7: READ d$(n): NEXT n 40 DIM m(12): REM lengths of months 50 FOR n=1 TO 12: READ m(n): NEXT n 100 REM input date 110 INPUT "day?";day 120 INPUT "month?";month 130 INPUT "year (20th century only)?";year 140 IF year<1901 THEN PRINT "20th century starts at 1901": GO TO 100 150 IF YEAR>2000 THEN PRINT "20th century ends at 2000": GO TO 100 160 IF month<1 THEN GO TO 210 170 IF MONTH>12 THEN GO TO 210 180 IF year/4-INT(year/4)=0 THEN LET m(2)=29: REM leap year 190 IF day>m(month) THEN PRINT "This month has only "; m(month);" days.": GO TO 500 200 IF day>0 THEN GO TO 300 210 PRINT "Stuff and nonsense. Give me a real date." 220 GO TO 500 300 REM convert date to number of days since start of century 310 LET y=year-1901 320 LET b=365*y+INT (y/4): REM number of days to start of year 330 FOR n=1 TO month-1: REM add on previous months 340 LET b=b+m(n): NEXT n 350 LET b=b+day 400 REM convert to day of week 410 LET b=b-7*INT (b/7)+1 420 PRINT day;"/";month;"/";year 430 FOR n=6 TO 3 STEP -1: REM remove trailing spaces 440 IF d$(b,n) <> " " THEN GO TO 460 450 NEXT n 460 LET e$=d$(b, TO n) 470 PRINT" is a "; e$; "day" 500 LET m(2)=28: REM restore February 510 INPUT "again?", a$ 520 IF a$="n" THEN GO TO 540 530 IF a$ <> "N" THEN GO TO 100 1000 REM days of week 1010 DATA "Mon", "Tues", "Wednes" 1020 DATA "Thurs", "Fri", "Satur", "Sun" 1100 REM lengths of months 1110 DATA 31, 28, 31, 30, 31, 30 1120 DATA 31, 31, 30, 31, 30, 31
This program handles yards, feet and inches.
10 INPUT "yards?",yd,"feet?",ft, "inches?",ins 40 GO SUB 2000: REM print the values 50 PRINT '" = "; 70 GO SUB 1000: REM the adjustment 80 GO SUB 2000: REM print the adjusted values 90 PRINT 100 GOTO 10 1000 REM subroutine to adjust yd, ft, in to the normal form for yards, feet and inches 1010 LET ins=36*yd+12*ft+ins: REM now everything is in inches 1030 LET s=SGN ins: LET ins=ABS ins: REM we work with in positive, holding its sign in s 1060 LET ft=INT (ins/12): LET ins=(ins-12*ft)*s: REM now ins is ok 1080 LET yd=INT (ft/3)*s: LET ft=ft*s-3*yd: RETURN 2000 REM subroutine to print yd, ft and in 2010 PRINT yd;"yd";ft;"ft";ins;"in";: RETURN
Here is a program to throw coins for the I Ching. (Unfortunately it produces the patterns upside down. but you might not worry about this.)
5 RANDOMIZE 10 FOR m=1 TO 6: REM for 6 throws 20 LET c=0: REM initialize coin total to 0 30 FOR n=1 TO 3: REM for 3 coins 40 LET c=c+2+INT (2*RND) 50 NEXT n 60 PRINT " "; 70 FOR n=1 TO 2: REM 1st for the thrown hexagram, 2nd for the changes 80 PRINT "___"; 90 IF c=7 THEN PRINT " "; 100 IF c=8 THEN PRINT " "; 110 IF c=6 THEN PRINT "X";: LET c=7 120 IF c=9 THEN PRINT "0";: LET c=8 130 PRINT "___ "; 140 NEXT n 150 PRINT 160 INPUT a$ 170 NEXT m: NEW
To use this, type it in and run it, and then press Enter five times to get the two hexagrams. Look these up in a copy of the Chinese Book of Changes. The text will describe a situation and the courses of action appropriate to it, and you must ponder deeply to discover the parallels between that and your own life. Press Enter a sixth time, and the program will erase itself this is to discourage you from using it frivolously.
Many people find the texts are always more apt than they would expect on grounds of chance; this may or may not be the case for you. In general, computers are pretty godless creatures.
Here is a program to play 'Pangolins'. You think up an animal, and the computer tries to guess what it is, by asking you questions that can be answered 'yes' or 'no'. If it's never heard of your animal before, it asks you to give it some question that it can use next time to find out whether someone's given it your new animal.
5 REM Pangolins 10 LET nq=100: REM number of questions and animals 15 DIM q$(nq,50): DIM a(nq,2): DIM r$(1) 20 LET qf=8 30 FOR n=1 TO qf/2-1 40 READ q$(n): READ a(n,1): READ a(n,2) 50 NEXT n 60 FOR n=n TO qf-1 70 READ q$(n): NEXT n 100 REM start playing 110 PRINT "Think of an animal.","Press any key to continue." 120 PAUSE 0 130 LET c=1: REM start with 1st question 140 IF a(c,1)=0 THEN GO TO 300 150 LET p$=q$(c): GO SUB 910 160 PRINT "?": GO SUB 1000 170 LET inn=1: IF r$="y" THEN GO TO 210 180 IF r$="Y" THEN GO TO 210 190 LET inn=2: IF r$="n" THEN GO TO 210 200 IF r$<>"N" THEN GO TO 150 210 LET c=a(c,inn): GO TO 140 300 REM animal 310 PRINT "Are you thinking of" 320 LET P$=q$(c): GO SUB 900: PRINT "?" 330 GO SUB 1000 340 IF r$="y" THEN GO TO 400 350 IF r$="Y" THEN GO TO 400 360 IF r$="n" THEN GO TO 500 370 IF r$="N" THEN GO TO 500 380 PRINT "Answer me properly when I'm","talking to you.": GO TO 300 400 REM guessed it 410 PRINT "I thought as much.": GO TO 800 500 REM new animal 510 IF qf>nq-1 THEN PRINT "I'm sure your animal is very", "interesting, but I don't have","room for it just now.": GO TO 800 520 LET q$(qf)=q$(c): REM move old animal 530 PRINT "What is it, then?": INPUT q$(qf+1) 540 PRINT "Tell me a question which dist ","inguishes between " 550 LET p$=q$(qf): GO SUB 900: PRINT " and" 560 LET p$=q$(qf+1): GO SUB 900: PRINT " " 570 INPUT s$: LET b=LEN s$ 580 IF s$(b)="?" THEN LET b=b-1 590 LET q$(c)=s$(TO b): REM insert question 600 PRINT "What is the answer for" 610 LET p$=q$(qf+1): GO SUB 900: PRINT "?" 620 GO SUB 1000 630 LET inn=1: LET io=2: REM answers for new and old animals 640 IF r$="y" THEN GO TO 700 650 IF r$="Y" THEN GO TO 700 660 LET inn=2: LET io=1 670 IF r$="n" THEN GO TO 700 680 IF r$="N" THEN GO TO 700 690 PRINT "That's no good. ": GO TO 600 700 REM update answers 710 LET a(c,inn)=qf+1: LET a(c,io)=qf 720 LET qf=qf+2: REM next free animal space 730 PRINT "That fooled me." 800 REM again? 810 PRINT "Do you want another go?": GO SUB 1000 820 IF r$="y" THEN GO TO 100 830 IF r$="Y" THEN GO TO 100 840 STOP 900 REM print without trailing spaces 905 PRINT " "; 910 FOR n=50 TO 1 STEP -1 920 IF p$(n)<>" " THEN GO TO 940 930 NEXT n 940 PRINT p$(TO n);: RETURN 1000 REM get reply 1010 INPUT r$: IF r$="" THEN RETURN 1020 LET r$=r$(1): RETURN 2000 REM initial animals 2010 DATA "Does it live in the sea",4,2 2020 DATA "Is it scaly",3,5 2030 DATA "Does it eat ants",6,7 2040 DATA "a whale", "a blancmange", "a pangolin", "an ant"
Here is a program to draw a Union Flag.
5 REM union flag 10 LET r=2: LET w=7: LET b=1 20 BORDER 0: PAPER b: INK w: CLS 30 REM black in bottom of screen 40 INVERSE 1 50 FOR n=40 TO 0 STEP -8 60 PLOT PAPER 0;7,n: DRAW PAPER 0;241,0 70 NEXT n: INVERSE 0 100 REM draw in white parts 105 REM St. George 110 FOR n=0 TO 7 120 PLOT 104+n,175: DRAW 0,-35 130 PLOT 151-n,175: DRAW 0,-35 140 PLOT 151-n,48: DRAW 0,35 150 PLOT 104+n,48: DRAW 0,35 160 NEXT n 200 FOR n=0 TO 11 210 PLOT 0,139-n: DRAW 111,0 220 PLOT 255,139-n: DRAW -111,0 230 PLOT 255,84+n: DRAW -111,0 240 PLOT 0,84+n: DRAW 111,0 250 NEXT n 300 REM St. Andrew 310 FOR n=0 TO 35 320 PLOT 1+2*n,175-n: DRAW 32,0 330 PLOT 224-2*n,175-n: DRAW 16,0 340 PLOT 254-2*n,48+n: DRAW-32,0 350 PLOT 17+2*n,48+n: DRAW 16,0 360 NEXT n 370 FOR n=0 TO 19 380 PLOT 185+2*n,140+n: DRAW 32,0 390 PLOT 200+2*n,83-n: DRAW 16,0 400 PLOT 39-2*n,83-n: DRAW 32,0 410 PLOT 54-2*n,140+n: DRAW -16,0 420 NEXT n 425 REM fill in extra bits 430 FOR n=0 TO 15 440 PLOT 255,160+n: DRAW 2*n-30,0 450 PLOT 0,63-n: DRAW 31-2*n,0 460 NEXT n 470 FOR n=0 TO 7 480 PLOT 0,160+n: DRAW 14-2*n,0 485 PLOT 255,63-n: DRAW 2*n-15,0 490 NEXT n 500 REM red stripes 510 INVERSE 1 520 REM St George 530 FOR n=96 TO 120 STEP 8 540 PLOT PAPER r;7,n: DRAW PAPER r;241,0 550 NEXT n 560 FOR n=112 TO 136 STEP 8 570 PLOT PAPER r;n,168: DRAW PAPER r;0,-113 580 NEXT n 600 REM St Patrick 610 PLOT PAPER r;170,140: DRAW PAPER r;70,35 620 PLOT PAPER r;179,140: DRAW PAPER r;70,35 630 PLOT PAPER r;199,83: DRAW PAPER r;56,-28 640 PLOT PAPER r;184,83: DRAW PAPER r;70,-35 650 PLOT PAPER r;86,83: DRAW PAPER r;-70,-35 660 PLOT PAPER r;72,83: DRAW PAPER r;-70,-35 670 PLOT PAPER r;56,140: DRAW PAPER r;-56,28 680 PLOT PAPER r;71,140: DRAW PAPER r;-70,35 690 INVERSE 0: PAPER 0: INK 7
If you're not British, have a go at drawing your own flag. Tricolours are fairly easy, although some of the colours - for instance the orange in the Irish flag - might present difficulties. If you're an American, you might be able to fit the character * in.
Here is a program to play hangman. One player enters a word, and the other guesses.
5 REM hangman 10 REM set up screen 20 INK 0: PAPER 7: CLS 30 LET x=240: GO SUB 1000: REM draw man 40 PLOT 238,128: DRAW 4,0: REM mouth 100 REM set up word 110 INPUT w$: REM word to guess 120 LET b=LEN w$: LET v$=" " 130 FOR n=2 TO b: LET v$=v$+" " 140 NEXT n: REM v$=word guessed so far 150 LET c=0: LET d=0: REM guess & mistake counts 160 FOR n=0 TO b-1 170 PRINT AT 20,n;" "; 180 NEXT n: REM write 's instead of letters 200 INPUT "Guess a letter ";g$ 210 IF g$="" THEN GO TO 200 220 LET g$=g$(1): REM 1st letter only 230 PRINT AT 0,c;g$ 240 LET c=c+1: LET u$=v$ 250 FOR n=1 TO b: REM update guessed word 260 IF w$(n)=g$ THEN LET v$(n)=g$ 270 NEXT n 280 PRINT AT 19,0;v$ 290 IF v$=w$ THEN GO TO 500: REM word guessed 300 IF v$<>u$ THEN GO TO 200: REM guess was right 400 REM draw next part of gallows 410 IF d=8 THEN GO TO 600: REM hanged 420 LET d=d+1 430 READ x0,y0,x,y 440 PLOT x0,y0: DRAW x,y 450 GO TO 200 500 REM free man 510 OVER 1: REM rub out man 520 LET x=240: GO SUB 1000 530 PLOT 238,128: DRAW 4,0: REM mouth 540 OVER 0: REM redraw man 550 LET x=146: GO SUB 1000 560 PLOT 143,129: DRAW 6,0, PI/2: REM smile 570 GO TO 800 600 REM hang man 610 OVER 1: REM rub out floor 620 PLOT 255,65: DRAW -48,0 630 DRAW 0,-48: REM open trapdoor 640 PLOT 238,128: DRAW 4,0: REM rub out mouth 650 REM move limbs 655 REM arms 660 PLOT 255,117: DRAW -15,-15: DRAW -15,15 670 OVER 0 680 PLOT 236,81: DRAW 4,21: DRAW 4, 21 690 OVER 1: REM legs 700 PLOT 255,66: DRAW -15,15: DRAW -15,-15 710 OVER 0 720 PLOT 236,60: DRAW 4,21: DRAW 4,-21 730 PLOT 237,127: DRAW 6,0,-PI/2: REM frown 740 PRINT AT 19,0;w$ 800 INPUT "again? ";a$ 810 IF a$="" THEN GO TO 850 820 LET a$=a$(1) 830 IF a$="n" THEN STOP 840 IF a$(1)="N" THEN STOP 850 RESTORE: GO TO 5 1000 REM draw man at column x 1010 REM head 1020 CIRCLE x,132,8 1030 PLOT x+4,134: PLOT x-4,134: PLOT x,131 1040 REM body 1050 PLOT x,123: DRAW 0,-20 1055 PLOT x,101: DRAW 0,-19 1060 REM legs 1070 PLOT x-15,66: DRAW 15,15: DRAW 15,-15 1080 REM arms 1090 PLOT x-15,117: DRAW 15,-15: DRAW 15,15 1100 RETURN 2000 DATA 120,65,135,0,184,65,0,91 2010 DATA 168,65,16,16,184,81,16,-16 2020 DATA 184,156,68,0,184,140,16,16 2030 DATA 204,156,-20,-20,240,156,0,-16