Articolo
11/18/2011

Math.Log10 Method

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Returns the base 10 logarithm of a specified number.

Namespace: System
Assembly: mscorlib (in mscorlib.dll)

Syntax

'Declaration
<SecuritySafeCriticalAttribute> _
Public Shared Function Log10 ( _
    d As Double _
) As Double

[SecuritySafeCriticalAttribute]
public static double Log10(
    double d
)

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.

Sign of d	Returns
Positive	The base 10 log of d; that is, log 10d.
Zero	NegativeInfinity
Negative	NaN
Equal to NaN	NaN
Equal to PositiveInfinity	PositiveInfinity

Remarks

Parameter d is specified as a base 10 number.

Examples

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

Module Example
   Public Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
      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.

using System;

class Example
{
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      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.

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

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