Windows Dev Center

Single.CompareTo Method (Single)

Compares this instance to a specified single-precision floating-point number and returns an integer that indicates whether the value of this instance is greater than, less than, or equal to the value of the specified single-precision floating-point number.

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

'Declaration
Public Function CompareTo ( _
	value As Single _
) As Integer

Parameters

value
Type: System.Single
A single-precision floating-point number to compare.

Return Value

Type: System.Int32
A signed number indicating the relative values of this instance and value.

Return Value

Description

Less than zero

This instance is less than value.

-or-

This instance is not a number (NaN) and value is a number.

Zero

This instance is equal to value.

-or-

Both this instance and value are not a number (NaN), PositiveInfinity, or NegativeInfinity.

Greater than zero

This instance is greater than value.

-or-

This instance is a number and value is not a number (NaN).

Implements

IComparable(Of T).CompareTo(T)

This method implements the System.IComparable(Of T) interface and performs slightly better than the Single.CompareTo method because it does not have to convert the value parameter to an object.

Note that, although an object whose value is NaN is not considered equal to another object whose value is NaN (even itself), the IComparable(Of T) interface requires that A.CompareTo(A) return zero.

Widening Conversions

Depending on your programming language, it might be possible to code a CompareTo method where the parameter type has fewer bits (is narrower) than the instance type. This is possible because some programming languages perform an implicit widening conversion that represents the parameter as a type with as many bits as the instance.

For example, suppose the instance type is Single and the parameter type is Int32. The Microsoft C# compiler generates instructions to represent the value of the parameter as a Single object, then generates a Single.CompareTo(Single) method that compares the values of the instance and the widened representation of the parameter.

Consult your programming language's documentation to determine if its compiler performs implicit widening conversions of numeric types.

Precision in Comparisons

The precision of floating-point numbers beyond the documented precision is specific to the implementation and version of the .NET Framework. Consequently, a comparison of two particular numbers might change between versions of the .NET Framework because the precision of the numbers' internal representation might change.

The following code example demonstrates generic and nongeneric versions of the CompareTo method for several value and reference types.


' This example demonstrates the generic and non-generic versions of the 
' CompareTo method for several base types.
' The non-generic version takes a parameter of type Object, while the generic
' version takes a type-specific parameter, such as Boolean, Int32, or Double.


Class Example
   Public Shared Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
      Dim nl As String = vbCrLf
      Dim msg As String = _
          "{0}The following is the result of using the generic and non-generic{0}" & _
          "versions of the CompareTo method for several base types:{0}"

      Dim now As DateTime = DateTime.Now
      ' Time span = 11 days, 22 hours, 33 minutes, 44 seconds
      Dim tsX As New TimeSpan(11, 22, 33, 44)
      ' Version = 1.2.333.4
      Dim versX As New Version("1.2.333.4")
      ' Guid = CA761232-ED42-11CE-BACD-00AA0057B223
      Dim guidX As New Guid("{CA761232-ED42-11CE-BACD-00AA0057B223}")

      Dim a1 As [Boolean] = True, a2 As [Boolean] = True
      Dim b1 As [Byte] = 1, b2 As [Byte] = 1
      Dim c1 As Int16 = -2, c2 As Int16 = 2
      Dim d1 As Int32 = 3, d2 As Int32 = 3
      Dim e1 As Int64 = 4, e2 As Int64 = -4
      Dim f1 As [Decimal] = -5.5D, f2 As [Decimal] = 5.5D
      Dim g1 As [Single] = 6.6F, g2 As [Single] = 6.6F
      Dim h1 As [Double] = 7.7, h2 As [Double] = -7.7
      Dim i1 As [Char] = "A"c, i2 As [Char] = "A"c
      Dim j1 As String = "abc", j2 As String = "abc"
      Dim k1 As DateTime = now, k2 As DateTime = now
      Dim l1 As TimeSpan = tsX, l2 As TimeSpan = tsX
      Dim m1 As Version = versX, m2 As New Version("2.0")
      Dim n1 As Guid = guidX, n2 As Guid = guidX

      ' The following types are not CLS-compliant.
      ' SByte, UInt16, UInt32, UInt64

      outputBlock.Text &= String.Format(msg, nl) & vbCrLf
      Try
         ' The second and third Show method call parameters are automatically boxed because
         ' the second and third Show method declaration arguments expect type Object.

         Show(outputBlock, "Boolean:  ", a1, a2, a1.CompareTo(a2), a1.CompareTo(CObj(a2)))
         Show(outputBlock, "Byte:     ", b1, b2, b1.CompareTo(b2), b1.CompareTo(CObj(b2)))
         Show(outputBlock, "Int16:    ", c1, c2, c1.CompareTo(c2), c1.CompareTo(CObj(c2)))
         Show(outputBlock, "Int32:    ", d1, d2, d1.CompareTo(d2), d1.CompareTo(CObj(d2)))
         Show(outputBlock, "Int64:    ", e1, e2, e1.CompareTo(e2), e1.CompareTo(CObj(e2)))
         Show(outputBlock, "Decimal:  ", f1, f2, f1.CompareTo(f2), f1.CompareTo(CObj(f2)))
         Show(outputBlock, "Single:   ", g1, g2, g1.CompareTo(g2), g1.CompareTo(CObj(g2)))
         Show(outputBlock, "Double:   ", h1, h2, h1.CompareTo(h2), h1.CompareTo(CObj(h2)))
         Show(outputBlock, "Char:     ", i1, i2, i1.CompareTo(i2), i1.CompareTo(CObj(i2)))
         Show(outputBlock, "String:   ", j1, j2, j1.CompareTo(j2), j1.CompareTo(CObj(j2)))
         Show(outputBlock, "DateTime: ", k1, k2, k1.CompareTo(k2), k1.CompareTo(CObj(k2)))
         Show(outputBlock, "TimeSpan: ", l1, l2, l1.CompareTo(l2), l1.CompareTo(CObj(l2)))
         Show(outputBlock, "Version:  ", m1, m2, m1.CompareTo(m2), m1.CompareTo(CObj(m2)))
         Show(outputBlock, "Guid:     ", n1, n2, n1.CompareTo(n2), n1.CompareTo(CObj(n2)))
         '
         outputBlock.Text &= String.Format("{0}The following types are not CLS-compliant:", nl) & vbCrLf
         outputBlock.Text &= String.Format("SByte, UInt16, UInt32, UInt64") & vbCrLf

      Catch e As Exception
         outputBlock.Text &= e.GetType().Name & vbCrLf
      End Try
   End Sub 'Main

   Public Shared Sub Show(ByVal outputBlock As System.Windows.Controls.TextBlock, ByVal caption As String, ByVal var1 As [Object], ByVal var2 As [Object], _
                          ByVal resultGeneric As Integer, ByVal resultNonGeneric As Integer)
      Dim relation As String

      outputBlock.Text &= caption
      If resultGeneric = resultNonGeneric Then
         If resultGeneric < 0 Then
            relation = "less than"
         ElseIf resultGeneric > 0 Then
            relation = "greater than"
         Else
            relation = "equal to"
         End If
         outputBlock.Text &= String.Format("{0} is {1} {2}", var1, relation, var2) & vbCrLf

         ' The following condition will never occur because the generic and non-generic
         ' CompareTo methods are equivalent.

      Else
         outputBlock.Text &= String.Format("Generic CompareTo = {0}; non-generic CompareTo = {1}", _
                            resultGeneric, resultNonGeneric) & vbCrLf
      End If
   End Sub 'Show
End Class 'Sample
'
'This example produces the following results:
'
'The following is the result of using the generic and non-generic versions of the
'CompareTo method for several base types:
'
'Boolean:  True is equal to True
'Byte:     1 is equal to 1
'Int16:    -2 is less than 2
'Int32:    3 is equal to 3
'Int64:    4 is greater than -4
'Decimal:  -5.5 is less than 5.5
'Single:   6.6 is equal to 6.6
'Double:   7.7 is greater than -7.7
'Char:     A is equal to A
'String:   abc is equal to abc
'DateTime: 12/1/2003 5:37:46 PM is equal to 12/1/2003 5:37:46 PM
'TimeSpan: 11.22:33:44 is equal to 11.22:33:44
'Version:  1.2.333.4 is less than 2.0
'Guid:     ca761232-ed42-11ce-bacd-00aa0057b223 is equal to ca761232-ed42-11ce-bacd-00
'aa0057b223
'
'The following types are not CLS-compliant:
'SByte, UInt16, UInt32, UInt64
'


Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Windows Phone

Show:
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