Math.Round Method (Double)
Rounds a double-precision floating-point value to the nearest integral value.
Assembly: mscorlib (in mscorlib.dll)
Parameters
- a
-
Type:
System.Double
A double-precision floating-point number to be rounded.
Return Value
Type: System.DoubleThe integer nearest a. If the fractional component of a is halfway between two integers, one of which is even and the other odd, then the even number is returned. Note that this method returns a Double instead of an integral type.
Note |
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For examples and comprehensive usage information about this and other overloads of the Round method, see the Round reference page. |
Notes to Callers:
Because of the loss of precision that can result from representing decimal values as floating-point numbers or performing arithmetic operations on floating-point values, in some cases the Round(Double) method may not appear to round midpoint values to the nearest even integer. In the following example, because the floating-point value .1 has no finite binary representation, the first call to the Round(Double) method with a value of 11.5 returns 11 instead of 12.
Module Example Public Sub Main() Dim value As Double = 11.1 For ctr As Integer = 0 To 5 value = RoundValueAndAdd(value) Next Console.WriteLine() value = 11.5 RoundValueAndAdd(value) End Sub Private Function RoundValueAndAdd(value As Double) As Double Console.WriteLine("{0} --> {1}", value, Math.Round(value)) Return value + .1 End Function End Module ' The example displays the following output: ' 11.1 --> 11 ' 11.2 --> 11 ' 11.3 --> 11 ' 11.4 --> 11 ' 11.5 --> 11 ' 11.6 --> 12 ' ' 11.5 --> 12
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
