ZX BASIC:Circle.Bas

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Program: circle.bas

 REM Sample circle drawing
 
 DIM i, r, x, y, q AS Float
 DIM ax, ay, zx, zy, dx, dy AS Ubyte
 
 x = 127
 y = 87
 r = 40
 q = 1 / r
 
 FOR i = 0 TO PI/2 STEP q
    dy = SIN(i) * r
    dx = COS(i) * r
 
    zx = x - dx
    zy = y - dy
    ax = x + dx
    ay = y + dy
 
    PLOT ax, ay
    PLOT zx, ay
    PLOT ax, zy
    PLOT zx, zy
 NEXT i