Sierpinski carpet: Difference between revisions

=={{header|Commodore BASIC}}==

<lang basic>100 PRINT CHR$(147); CHR$(18); "**** SIERPINSKI CARPET ****"

110 PRINT

120 INPUT "ORDER"; O$

130 O = VAL(O$)

140 IF O < 1 THEN 120

150 PRINT

160 SZ = 3 ↑ O

170 FOR Y = 0 TO SZ - 1

180 :FOR X = 0 TO SZ - 1

190 : CH$ = "#"

200 : X1 = X

210 : Y1 = Y

220 : IF (X1 = 0) OR (Y1 = 0) THEN 290

230 : X3 = X1 - 3 * INT(X1 / 3)

240 : Y3 = Y1 - 3 * INT(Y1 / 3)

250 : IF (X3 = 1) AND (Y3 = 1) THEN CH$ = " ": GOTO 290

260 : X1 = INT(X1 / 3)

270 : Y1 = INT(Y1 / 3)

280 : GOTO 220

290 : PRINT CH$;

300 :NEXT X

310 PRINT

320 NEXT Y

</lang>

{{Out}}

All of the Commodore 8-bits have a 25-line display, so orders 3 and up scroll the top of the carpet off the screen. Orders 4+ additionally require at least 81 columns, and even a PET or C128 maxes out at 80. So we'll settle for an order-2 demonstration:

<pre>**** SIERPINSKI CARPET ****

ORDER? 2

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# ## ## #

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# # # #

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# ## ## #

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READY.</pre>