High Resolution Bar Graphs For The Pet

[Blacklord]

The program listed here is a general purpose bar graphing program illustrating the high resolution bars. The bar graph is loaded into an array first before it is plotted on the screen. This is done for flexibility. To switch from vertical to horizontal graphs requires rewriting only the print routine (lines 1000 and up) and putting the appropriate graphics characters in the array X$ (lines 110 and 115). The rest of the program remains the same. You can change the data plotted by retyping the DATA statement (line 150) and changing the heading in K$ (line 160). You do not need to worry about the maximum value of the data. The program calculates (on line 280) a maximum bar length so that the largest data value is plotted nine-tenths of the maximum allowable bar length. If you prefer line 280 can be changed to set a definite ceiling. Be careful though. The program is not protected against data larger than the maximum bar length.

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10 REM ************************
60 REM ************************
100 DIM M$ (11, 20), Y(12), X$(8)
105 REM X$ CONTAINS GRAPHICS CHARACTERS
106 REM FOR MAKING THE BAR
110 X$(1) = "$": X$(2) = "o": X$(3) = "y": X$(4) = "b": X$(5) = "{REV}x{OFF}": X$(6) = "{REV}w{OFF}"
115 X$(7) = "{REV}c{OFF}": X$(8) = "{REV}{OFF}"
119 REM MOVE CURSOR DOWN CHARACTERS
120 P$ = "{24 DOWN}"
125 REM HOME AND UP, BACK CHARACTERS
130 H$ = "{HOME}": U$ = "{UP}{LEFT}"
140 REM DATA TO BE PLOTTED ON THE BAR
150 DATA 75.36, 91.53, 61.29, 39.56, 21.78, 11.4, 11.39, 10, 1, 1.5, 24.69, 35.67
155 REM K$ IS THE TITLE OF THE GRAPH
160 K$ = "NATURAL GAS BILLS"
190 REM READ THE VALUES TO BE PLOTTED
200 FOR X = l TO 12
210 READ Y(X)
220 NEXT X
230 Y(0) = Y(1)
250 FOR X = 2 TO 12
260 IF Y(X)>Y(0) THEN Y(0) = Y(X)
270 NEXT X
275 REM SET MAXIMUM BAR LENGTH, Y(0),
276 REM TO BE 10/9 TIMES LARGEST VALUE
280 Y(0) = 10*Y(0)/9
300 FOR M = 1 TO 12
301 N = M-1
305 REM CALCULATE THE NUMBER OF PRINT
306 REM LINES LONG THE BAR WILL BE
310 Z = Y(M)*20/Y(0)
315 REM Z% IS NUMBER OF WHOLE LINES
316 REM TALL THEN BAR IS
320 Z% = INT(Z)
325 REM R% IS NUMBER OF RASTER LINES
326 REM TO BE PRINTED ON THE Z% + 1
330 R% = INT((Z-Z%)*8)
336 IF Z% = 0 THEN 530
500 FOR P = 1 TO Z%
510 M$ (N,P) = X$(8)
520 NEXT P
530 IF R% = 0 THEN 550
540 M$(N, Z% + 1)= X$ (R%)
550 NEXT M
1000 REM PRINT THE BAR GRAPH
1004 PRINT"{CLEAR}"
1005 REM WRITE THE GRAPH TITLE
1006 PRINT SPC(20-LEN(K$)/2);K$
1009 REM PUT BAR IDENT. AT BOTTOME OF SCREEN
1010 PRINT "{HOME}";P$;"  J  F  M A~ M  J  J  A  S  O  N  D";
1020 FOR M = 1 TO 12
1021 N = M-1
1025 REM POSITION CURSOR READY TO DRAW
1026 REM THE NEXT BAR
1030 PRINT H$;LEFT$(P$, 21);SPC(3*M);
1035 REM DRAW THE ENTIRE BAR INCLUDING BLANKS
1040 FOR B = 1 TO 20
1050 PRINT M$(N, B);U$;
1060 NEXT B
1070 NEXT M
1080 GETA$ : IFA$ = ""THEN 1080
1100 END