Data Validation and Error Trapping

Tipcorner - binary file access

Updating the Open Source Editor

Spotlight on Polar Coordinates

polar1.bas by Nally

atari2.bas by Nally

polar coordinate demo

'***********************************************

'

'Atan2.bas by Nally + April 2000

'Released as open source

'

'A function called ATAN2() is provided herein.

'ATAN2() takes two arguements: cartesian x and y

'coordinates. It returns an angle, phi, in

'radians.

'

'ATAN2() differs from ATN() in this regard:

'while ATN() only returns an angle between

'-pi/2 and +pi/2, ATAN2() will return any

'angle in the full circle.

'

'The user should not call the function if both

'x and y = 0. This corresponds to a point at

'the origin of the coordinate system where

'the angle phi has no meaning.

'

'***********************************************

pi = 3.14159265

Print " " Print "Note: Input real numbers for" Print " x and y. Either x or y" Print " or both must be non-zero." Print " " Print "** INPUT **" Print " "

Input "x = "; x Input "y = "; y

Print " " Print "** OUTPUT **" Print " "

phiRads = ATAN2(x, y) phiDegs = 360 * (phiRads / (2 * pi)) R = (x^2 + y^2)^(1/2) Print "Cartesion Coordinates of Q....Q("; x; ", "; y; ")" Print " " Print "ATAN2 in radians.............."; phiRads Print "ATAN2 in degrees.............."; phiDegs Print "Distance to Q................."; R Print " " Print "Polar Coordinates of Q........Q("; phiRads; ", "; R;")"

End

Function ATAN2(x, y) pi = 3.14159265 Result$ = "Undetermined" If (x = 0) and (y > 0) Then ATAN2 = pi / 2 Result$ = "Determined" End If If (x = 0) and (y < 0) Then ATAN2 = 3 * pi / 2 Result$ = "Determined" End If If (x > 0) and (y = 0) Then ATAN2 = 0 Result$ = "Determined" End If If (x < 0) and (y = 0) Then ATAN2 = pi Result$ = "Determined" End If

If Result$ = "Determined" Then [End.of.function]

BaseAngle = Atn(abs(y)/abs(x)) If (x > 0) and (y > 0) Then ATAN2 = BaseAngle If (x < 0) and (y > 0) Then ATAN2 = pi - BaseAngle If (x < 0) and (y < 0) Then ATAN2 = pi + BaseAngle If (x > 0) and (y < 0) Then ATAN2 = 2*pi - BaseAngle

[End.of.function]

End Function