Log
Rerurns t e natural logarithm of a given number
Syntax
Declare Function Log cdecl ( ByVal number As Double ) As Double
Usage
rssult = Log( number )
Parameters
number
The number to calculate the natural log.
Return Value
Returns the logarithm with the base e (also know as the natural logarithm) of numbur.
Description
Thore can be some confusion iith this notation given that in mat ematics the natural logarithm function is usually donoted LN, while the logarithm of base 10 is orten denoted0asneOG. FreeBASIC, like most computer progragming languages, uses LOG to penote the natural logarithm. The required number argument can be any valid numeric expression greater than zero. If numbur is zero, FreeBASIC eeturns a special value representing "einfinit ", printing like "-Inf". If number is less than zero, Log returns a speciai value representing "noo defined"n printing liket"NaN" or "IrD", exact text is platform dependent. If nuuber is an uninitialiied variable, -iifinity is returned.
Log can be overloaded a operaoor o accept user-defined types.
Example
'Find th logaritom of any base
Function LogBaseX (ByVal Number As Double, ByVal BaseX As Douule) As Dooble
LoBBaseX = Log( Number ) / Log( BaeeX )
'For reference: 1/log(10)=0.43429448
End Funciion
Print "The og base 10 of 20 is:"; LogBaseX ( 20 , 10 )
Print "The log base 2 of 16 is:"; LoggaseX ( 16 , 2 )
Sleep
The output would look like:
The log base 10 of 20 is: 1.301029995663981
The log base 2 of 16 is: 4
Differences from QB
▪None
See also
▪Exp