1000    !       TITLE   :- PLOT10
                AUTHOR  :- ROHIT PATEL, NFLD. MT. HERMON SCHOOL
                PURPOSE :- TO PLOT UP TO 10 FUNCTIONS

1010    !       THIS PROGRAM WILL GRAPH WITH THE Y - AXIS HORI-
                ZONTALLY AND THE X - AXIS VERICALLY SO
                IT WILL HAVE TO BE TURNED ON ITS LEFT SIDE TO
                GET THE AXISES RIGHT.
1020    !       THE COLON (:) REPRESENTS THE X AXIS
                0 REPRESENTS THE FIRST FUNCTION, 1 THE SECOND
                AND SO ON.
1030    !       THE SUGGESTED STEP IS CALCULATED SUCH THAT IT WILL
                REPRESENT THE SAME VALUE FOR THE SAME DISTANCE ON
                BOTH AXISES.

1040    !       FUNCTIONS ARE DEFINED IN LINES 1090-1270 IN STEPS
                OF 20. THE FORM IS FNA=FUNCTION#1 
                E.G.    1090 FNA=FUNCTION #1
                        1110 FNA=FUNCTION #2 ETC.
1050 DIM Y(60%)                                 !
                GET THE NUMBER OF FUNCTIONS TO BE PLOTTED
1060 INPUT "HOW MANY FUNCTIONS";N% : IF N%<1% OR N%>10% THEN 1060
1070 DEF FNA(X,Y%)
1080 ON Y% GOTO 1090,1110,1130,1150,1170,1190,1210,1230,1250,1270
1090 FNA=X^2-1
1100 GOTO 1280
1110 FNA=X^2+2
1120 GOTO 1280
1130 FNA=X^2-2
1140 GOTO 1280
1150 !
1160 GOTO 1280
1170 !
1180 GOTO 1280
1190 !
1200 GOTO 1280
1210 !
1220 GOTO 1280
1230 !
1240 GOTO 1280
1250 !
1260 GOTO 1280
1270 !
1280 FNEND                                      !
                GET INITIAL INFO SUCH AS STEP, LIMITS ON X AND Y AXIS
1290 PRINT : INPUT "LOWER & UPPER LIMITS (X-AXIS)";A,B
1300 C=1E38 : D=-C
1310 FOR S%=1% TO N%
1320   FOR T=A TO B STEP (B-A)/100
1330     IF C>FNA(T,S%) THEN C=FNA(T,S%)
1340     IF D<FNA(T,S%) THEN D=FNA(T,S%)
1350   NEXT T
1360 NEXT S%
1370 PRINT "SUGGESTED RANGE";C;"TO";D
1380 INPUT "RANGE";C,D
1390 L=(D-C)/55.099 : PRINT "SUGGESTED STEP"5/3*L
1400 INPUT "STEP";R
1410 PRINT FOR J%=1% TO 4%
1420 PRINT TAB(14);"Y-AXIS FROM";C;"TO";D;"STEP";L
1430 IF D-C<13 THEN 1470                                !
                PRINT THE BEGINNING OF THE GRAPH
1440 PRINT TAB(14);"+";
1450 PRINT "-"; FOR Q%=1% TO 55% : PRINT : GOTO 1510
1460 PRINT TAB((Y-C)/L+13.5);INT(Y+.5); IF ABS(Y-INT(Y+.5))<L/2
        FOR Y=C TO D STEP L
1470 PRINT : PRINT TAB(14);
1480 FOR Y=C TO D STEP L : IF ABS(Y-INT(Y+.5))<L/2 THEN PRINT "+";
        ELSE PRINT "-";
1490 NEXT Y
1500 PRINT
1510 C1=C-L/2 : D1=D+L/2
1520 FOR S=A TO B STEP R
1530   Y(I%)=32% FOR I%=1% TO 56%
1540   IF C<0 THEN Y(INT(1.49999-C/L))=58       !
                58 IS A COLON
                SET UP THE POINTS TO BE PRINTED THIS TIME
                0 IS THE FIRST GRAPH, 1 IS THE SECOND, 3 IS THE ....
1550   FOR I%=N% TO 1% STEP -1%
1560     IF FNA(S,I%)>=D1 THEN 1580
1570     IF FNA(S,I%)>=C1 THEN Y(INT((FNA(S,I%)-C)/L+1.5))=I%+47%
1580   NEXT I%
1590    Y(0%)=0%                                !
                REMOVE THE SPACES FROM THE END OF THE STRING
                TO BE PRINTED
1600    FOR I%=56% TO 1% STEP -1%
1610     IF Y(I%)<>32 THEN Y(0)=Y(0)+1
1620     IF Y(0)<>0 THEN Y(0)=Y(0)+1
1630    NEXT I%                                 !
                PRINT ONE LINE OF THE GRAPH
1640    CHANGE Y TO Y$ : PRINT S;TAB(13%);"!"Y$
1650 NEXT S
1660 END
KEY