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.NET Development
.NET Framework 4
System
Math Class
Math Methods
 Log10 Method
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.NET Framework Class Library
Math..::.Log10 Method

Returns the base 10 logarithm of a specified number.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)
Visual Basic
Public Shared Function Log10 ( _
    d As Double _
) As Double
C#
public static double Log10(
    double d
)
Visual C++
public:
static double Log10(
    double d
)
F#
static member Log10 : 
        d:float -> float 

Parameters

d
Type: System..::.Double
A number whose logarithm is to be found.

Return Value

Type: System..::.Double
One of the values in the following table.

d parameter

Return value

Positive

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

Zero

NegativeInfinity

Negative

NaN

Equal to NaN

NaN

Equal to PositiveInfinity

PositiveInfinity

Parameter d is specified as a base 10 number.

The following example uses the Log10 method to return the base 10 logarithm for selected values.

Visual Basic
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.
C#
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.

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
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