Char.CompareTo Method (Char)

Compares this instance to a specified Char object and returns an integer that indicates whether this instance precedes, follows, or has the same position in the sort order as the specified Char value.

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

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

Parameters

value
Type: System.Char
A Char object to compare.

Return Value

Type: System.Int32
A signed number indicating the position of this instance in the sort order in relation to the value parameter.

Return Value

Description

Less than zero

This instance precedes value.

Zero

This instance has the same position in the sort order as value.

Greater than zero

This instance follows value.

Implements

IComparable(Of T).CompareTo(T)

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

The comparison performed by this method is based on the encoded values of this instance and value, not their lexicographical characteristics.

If the CompareTo method parameter type has fewer bits (is narrower) than the instance type, some programming languages perform an implicit widening conversion that transforms the value of the parameter into a value with more bits.

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

Typically, implicit widening conversions are performed on numeric types. Consult your programming language's documentation to determine if its compiler performs widening conversions. If the instance and parameter types mismatch and a suitable conversion is not available, the compiler generates instructions to box the parameter and invoke the CompareTo overload that takes an Object parameter.

The following example demonstrates generic and non-generic 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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