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BASIC.CIRCLE.bas
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BASIC Source File
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2023-02-26
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948b
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38 lines
10 REM **********************
20 REM * BASIC.CIRCLE *
30 REM * BY BRENT IVERSON *
40 REM * COYPRIGHT (C) 1988 *
50 REM * BY MICROSPARC, INC *
60 REM * CONCORD, MA 01742 *
70 REM **********************
80 :
90 REM ---SET CIRCLE POSITION
100 REM AND RADIUS
110 :
120 A = 140:B = 80:R = 70
130 :
140 REM ---CALL CIRCLE-GENERATOR
150 :
160 HGR : HCOLOR= 3
170 GOSUB 220
180 END
190 :
200 REM ---MAIN LOOP
210 :
220 X = 0:Y = R:D = 3 -2 *R
230 GOSUB 370
240 IF D <0 THEN D = D +4 *X +6: GOTO 260
250 D = D +4 *(X -Y) +10:Y = Y -1
260 X = X +1
270 IF X <Y THEN 230
280 IF X = Y THEN GOSUB 370
290 RETURN
300 :
310 REM ---HPLOT POINTS IN 8
320 REM QUADRANTS. NOTE THAT
330 REM NO CHECKING FOR
340 REM SCREEN LIMITS IS
350 REM EVER DONE!
360 :
370 HPLOT A +X,B +Y: HPLOT A +Y,B +X: HPLOT A +Y,B -X: HPLOT A +X,B -Y: HPLOT A -X,B -Y: HPLOT A -Y,B -X: HPLOT A -Y,B +X: HPLOT A -X,B +Y
380 RETURN