qb45advr.hlp (Topic list)
Important Notice
The pages on this site contain documentation for very old MS-DOS software, purely for historical purposes. If you're looking for up-to-date documentation, particularly for programming, you should not rely on the information found here, as it will be woefully out of date.
SIN Function Programming Example
  QuickSCREEN      Details     Example      Contents      Index
──────────────────────────────────────────────────────────────────────────────
SIN Function Programming Example
 
The example plots the graph of the polar equation r = 1 + sin n (Θ). This
figure is sometimes known as a cardioid, owing to its resemblance to a
heart when n equals 1.
 
'***Programming example for the SIN function***
CLS
CONST PI = 3.141593
SCREEN 1 : COLOR 1,1             'Medium resolution, blue background.
WINDOW (-3,-2)-(3,2)             'Convert screen to Cartesian coordinates.
INPUT "Number of petals = ", N
CLS
PSET (1,0)                       'Set initial point.
FOR Angle = 0 TO 2*PI STEP .02
   R = 1 + SIN(N*Angle)          'Polar equation for "flower."
   X = R * COS(Angle)            'Convert polar coordinates to
   Y = R * SIN(Angle)            'Cartesian coordinates.
   LINE -(X,Y)                   'Draw line from previous point to new point.
NEXT
END