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1000    !       TITLE   :- XYPLOT
                AUTHOR  :- ROHIT PATEL, NFLD. MT. HERMON SCHOOL
                PURPOSE :- TO PLOT A FUNCTION WITH THE X AXIS
                        HORIZONTALLY AND THE Y AXIS VERICALLY
1100    !       INPUT THE FOLLOWING WHEN REQUESTED:
                  I  THIS IS A REQUEST FOR THE STEP (IN THE DOMAIN)
                  DOMAIN  IS A REQUEST FOR THE LIMITS ON THE X AXIS
                  RANGE   IS A REQUEST FOR THE LIMITS ON THE Y AXIS
1200    !       IF THE DIFFERENCE IN 'RANGE' IS ZERO THEN THIS PROGRAM
                WILL AUTOMATICALLY CALCULATE THE RANGE FOR YOU

1300 DIM A$(55%) : A$(1%)="!"+SPACE$(59%) : A$(I%)=A$(1%) FOR
        I%=2% TO 55%
        !       DEFINE THE FUNCTION AND GET DOMAIN AND
                RANGE. IF THE LIMITS ON THE RANGE ARE THE
                SAME THEN FIGURE OUT THE RANGE AUTOMATICALLY
1400 DEF FNA(X)=X^2-1
1500 INPUT "I";I !I FOR INCREMANT
1600 INPUT "DOMAIN";D,D0 : INPUT "RANGE";R,R0 : IF R<>R0 THEN 1800
1700 R=1E+38 : R0=-R : FOR X=D TO D0 STEP I : R0=FNA(X) IF FNA(X)>R0 :
        R=FNA(X) IF FNA(X)<R : NEXT X
1800 M0=59/(D0-D) : M1=54/(R0-R) : B0=1-INT(M0*D+.5) : B1=1-INT(M1*R+.5)
1900    !       SEE IF THE Y AXIS EXISTS.  IF IT DOES THEN FIGURE
                IT OUT NOW
2000 IF B0>0 AND B0<=60 THEN A$(X)=LEFT(A$(X),B0)+":"+RIGHT
        (A$(X),B0+2) FOR X=1 TO 55
2100    !       FIGURE OUT THE X AXIS AND SET IT UP
2200 IF B1>0 AND B1<=55 THEN A$(B1)="" : A$(B1)=A$(B1)+"-" FOR X=1 TO 55
2300 FOR X=D TO D0 STEP I : R1=M1*FNA(X)+B1 : D1=M0*X+B0 :
        IF R1<1 OR R1>55 THEN 2400 ELSE A$(R1)=LEFT(A$(R1),D1)+"*"
        +RIGHT(A$(R1),D1+2%)
2400 NEXT X : PRINT "-"; FOR X=1 TO 55 : & : & : & : & : & :
        PRINT TAB(13%);"Y - AXIS FROM";R;"TO";R0;"STEP";(R0-R)/55 :
        PRINT TAB(13%);"X - AXIS FROM";D;"TO";D0;"STEP";(D0-D)/60 :
        PRINT : GOTO 2800 IF D0-D>12 : L=(D0-D)/60
2500 PRINT TAB((X-D)/L+10.5);INT(X+.5); IF ABS(X-INT(X+.5))<L/2
        FOR X=D TO D0 STEP L : & : & TAB(11%); :
        FOR X=D TO D0 STEP L
2600 IF ABS(X-INT(X+.5))<L/2 THEN &"+"; ELSE &"-";
2700 NEXT X : &
2800 FOR X=55 TO 1 STEP -1
2900 IF A$(X)<>"" AND RIGHT(A$(X),LEN(A$(X)))=" " THEN A$(X)=LEFT
        (A$(X),LEN(A$(X))-1) : GOTO 2900
3000 PRINT USING "#.#####^^^^",(X-B1)/M1;
3100 PRINT A$(X) : NEXT X : & : & : & : &"-"; FOR X=1 TO 55 : & : &
3200 END
KEY