Math.Log10(Double) Method
Definition
Important
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Returns the base 10 logarithm of a specified number.
public:
static double Log10(double d);
public static double Log10 (double d);
static member Log10 : double > double
Public Shared Function Log10 (d As Double) As Double
Parameters
 d
 Double
A number whose logarithm is to be found.
Returns
One of the values in the following table.
d parameter
 Return value 

Positive  The base 10 log of d ; that is, log 10d .

Zero  NegativeInfinity 
Negative  NaN 
Equal to NaN  NaN 
Equal to PositiveInfinity  PositiveInfinity 
Examples
The following example uses the Log10 method to return the base 10 logarithm for selected values.
using System;
public class Example
{
public static void Main()
{
double[] numbers = {1, 0, .105, .5, .798, 1, 4, 6.9, 10, 50,
100, 500, 1000, Double.MaxValue};
foreach (double number in numbers)
Console.WriteLine("The base 10 log of {0} is {1}.",
number, Math.Log10(number));
}
}
// The example dislays the following output:
// The base 10 log of 1 is NaN.
// The base 10 log of 0 is Infinity.
// The base 10 log of 0.105 is 0.978810700930062.
// The base 10 log of 0.5 is 0.301029995663981.
// The base 10 log of 0.798 is 0.0979971086492706.
// The base 10 log of 1 is 0.
// The base 10 log of 4 is 0.602059991327962.
// The base 10 log of 6.9 is 0.838849090737255.
// The base 10 log of 10 is 1.
// The base 10 log of 50 is 1.69897000433602.
// The base 10 log of 100 is 2.
// The base 10 log of 500 is 2.69897000433602.
// The base 10 log of 1000 is 3.
// The base 10 log of 1.79769313486232E+308 is 308.254715559917.
Module Example
Public Sub Main()
Dim numbers() As Double = {1, 0, .105, .5, .798, 1, 4, 6.9, 10, 50, _
100, 500, 1000, Double.MaxValue}
For Each number As Double In numbers
Console.WriteLine("The base 10 log of {0} is {1}.", _
number, Math.Log10(number))
Next
End Sub
End Module
' The example displays the following output:
' The base 10 log of 1 is NaN.
' The base 10 log of 0 is Infinity.
' The base 10 log of 0.105 is 0.978810700930062.
' The base 10 log of 0.5 is 0.301029995663981.
' The base 10 log of 0.798 is 0.0979971086492706.
' The base 10 log of 1 is 0.
' The base 10 log of 4 is 0.602059991327962.
' The base 10 log of 6.9 is 0.838849090737255.
' The base 10 log of 10 is 1.
' The base 10 log of 50 is 1.69897000433602.
' The base 10 log of 100 is 2.
' The base 10 log of 500 is 2.69897000433602.
' The base 10 log of 1000 is 3.
' The base 10 log of 1.79769313486232E+308 is 308.254715559917.
Remarks
Parameter d
is specified as a base 10 number.
This method calls into the underlying C runtime, and the exact result or valid input range may differ between different operating systems or architectures.