williams-et-al-1983-apple-ii-computer-graphics

126 APPLE II COMPUTER GRAPHICS670 X = 24 + I * SP%680 IF X < 280 THEN DRAW 11 AT X , 159690 NEXT I700 VTAB (21)710 PRINT " J F M A M J J A S 0 N D J F MA E A P A U U U E C 0 E A E AN B R R Y N L G P T V C N B R";720 VTAB (20)730 REM740 REM ********************750 REM * PLOT DATA POINTS *760 REM ********************770 REM780 HCOLOR = 7790 HPLOT 24, 160-DP(0) * SCL800 FOR I = 1 TO NP%-1810 X = 24 + I * SP%820 Y = DP (I) * SCL830 IF X > 279 THEN PRINT CHR$ ( 7) ;"CHART TOO WIDE" : GOTO 860 : REM (END )840 HPLOT TO X ,160-Y850 NEXT I860 END900 REM910 REM **************920 REM * DATA TABLE *930 REM **************940 REM950 DATA 15 , 18960 DATA 100,130 ,90,80 ,100,210,170 ,60,120,30 ,50,40,100, 80, 90Listing 11-3. Line graph.You may change the data plotted by changing the values given in line960. The numbers on the vertical axis will change accordingly, but will stillincrement by 20. The increment for the vertical scale may be adju sted inline 520, but we will talk more about that soon. The fi rst value in line 950gives the number of data points to be plotted, and the second item indicatesthe horizontal spacing between plots. Both those numbers may bealtered and the program will behave properly, except for the horizontallabels which remain fixed.After you have played for a while, let's look at some of the more interestingparts of this program.90 PRINT CHR$ ( 4) ; "BLOAD NUMBER TABLE, A$30W'100 POKE 232,0: POKE 233 ,3110 SCALE = 1