1 3REM X Y P L O T
 2 9 LET J=0
 3 10 GO TO 610
 4 11 IF J=0 THEN 130
 5 12 RETURN
 6 20 PRINT "                                XYPLOT"
 7 130 PRINT
 8 140 PRINT "WHAT ARE  YMIN,YMAX,XMIN,XMAX,DELX";
 9 150 INPUT Q0,Q1,Q2,Q3,Q4
10 160 LET Q5=(Q1-Q0)/60
11 170 LET Q6=0
12 180 LET J=2
13 190 FOR X = Q2 TO Q3 STEP Q4
14 200 GOSUB 10
15 210 IF Q6 = 0 THEN 470
16 220 IF Q6 = 20 THEN 250
17 230 PRINT " . ";
18 240 GOTO 270
19 250 PRINT " - ";
20 260 LET Q6 = 10
21 270 IF Y > Q1 THEN 440
22 280 IF Y < Q0 THEN 440
23 290 LET Q7 = Q0 + 2*Q5
24 300 LET Z=Q7+0.5*Q5
25 310 IF Z<Y THEN 410
26 320 LET Q6 = Q6 + 1
27 330 IF Z-Y>=2*Q5 THEN 390
28 340 IF Z-Y>=Q5 THEN 370
29 350 PRINT "  +"
30 360 GOTO 530
31 370 PRINT " +"
32 380 GOTO 530
33 390 PRINT "+"
34 400 GOTO 530
35 410 LET Q7 = Q7 + 3*Q5
36 420 PRINT "   ";
37 430 GOTO 300
38 440 PRINT "OFF SCALE:  (X,Y) =  ";X;",  ";Y
39 450 LET Q6 = Q6 + 1
40 460 GOTO 530
41 470 PRINT
42 480 PRINT "FOR X:    TOP = ";Q2;" BOTTOM = ";Q3;" INCREMENT = ";Q4
43 490 PRINT "FOR Y:   LEFT = ";Q0;"  RIGHT = ";Q1;" INCREMENT = ";Q5
44 500 PRINT
45 510 PRINT "   I.........I.........I.........I.........I.........I.........I"
46 520 GOTO 250
47 530 NEXT X
48 540 PRINT
49 550 PRINT "TYPE '0' TO STOP OR '1' TO CHANGE LIMITS.  WHICH";
50 560 INPUT Q8
51 570 IF Q8 = 0 THEN 9999
52 580 IF Q8 = 1 THEN 130
53 590 PRINT
54 600 GOTO 540
55 610 PRINT
56 620 PRINT "THIS PROGRAM WILL PLOT SINGLE-VALUED FUNCTIONS OF X,"
57 630 PRINT "WITH X ON THE VERTICAL AXIS.  TO USE, TYPE:"
58 640 PRINT
59 650 PRINT "   10 LET Y= (THE FUNCTION TO BE PLOTTED)"
60 660 PRINT "   RUN"
61 670 PRINT
62 680 PRINT "DURING RUNNING, THE PROGRAM WILL ASK FOR YMIN AND"
63 690 PRINT "YMAX (THE LIMITS ON THE HORIZONTAL Y-AXIS), FOR"
64 700 PRINT "XMIN AND XMAX (THE LIMITS ON THE VERTICAL X-AXIS),"
65 710 PRINT "AND FOR DELX, THE INCREMENT TO BE USED ALONG THE"
66 720 PRINT "X-AXIS.  NOTE: LINES 70-99 OF THE PROGRAM MAY BE"
67 730 PRINT "USED AS DESIRED TO EXPRESS COMPLICATED FUNCTIONS."
68 9999 END