VB.NET Single结构体代码示例

Module Example
   Public Sub Main()
      Dim value As Single = .2
      Dim result1 As Single = value * 10
      Dim result2 As Single
      For ctr As Integer = 1 To 10
         result2 += value
      Next
      Console.WriteLine(".2 * 10:           {0:R}", result1)
      Console.WriteLine(".2 Added 10 times: {0:R}", result2)
   End Sub
End Module

Module Example
   Public Sub Main()
      Dim value As Single = 123.456
      Dim additional As Single = Single.Epsilon * 1e15
      Console.WriteLine($"{value} + {additional} = {value + additional}")
   End Sub
End Module

Module Example
   Public Sub Main()
      Dim values() As Single = { 10.01, 2.88, 2.88, 2.88, 9.0 }
      Dim result As Single = 27.65
      Dim total As Single
      For Each value In values
         total += value
      Next
      If total.Equals(result) Then
         Console.WriteLine("The sum of the values equals the total.")
      Else
         Console.WriteLine("The sum of the values ({0}) does not equal the total ({1}).",
                           total, result) 
      End If     
   End Sub
End Module

' 导入命名空间
Imports System.IO

Module Example
   Public Sub Main()
      Dim sw As New StreamWriter(".\Singles.dat")
      Dim values() As Single = { 3.2/1.11, 1.0/3, CSng(Math.PI)  }
      For ctr As Integer = 0 To values.Length - 1
         sw.Write(values(ctr).ToString())
         If ctr <> values.Length - 1 Then sw.Write("|")
      Next      
      sw.Close()
      
      Dim restoredValues(values.Length - 1) As Single
      Dim sr As New StreamReader(".\Singles.dat")
      Dim temp As String = sr.ReadToEnd()
      Dim tempStrings() As String = temp.Split("|"c)
      For ctr As Integer = 0 To tempStrings.Length - 1
         restoredValues(ctr) = Single.Parse(tempStrings(ctr))   
      Next 

      For ctr As Integer = 0 To values.Length - 1
         Console.WriteLine("{0} {2} {1}", values(ctr), 
                           restoredValues(ctr),
                           If(values(ctr).Equals(restoredValues(ctr)), "=", "<>"))
      Next
   End Sub
End Module

' 导入命名空间
Imports System.IO

Module Example
   Public Sub Main()
      Dim sw As New StreamWriter(".\Singles.dat")
      Dim values() As Single = { 3.2/1.11, 1.0/3, CSng(Math.PI)  }
      For ctr As Integer = 0 To values.Length - 1
         sw.Write("{0:G9}{1}", values(ctr), 
                  If(ctr < values.Length - 1, "|", ""))
      Next      
      sw.Close()
      
      Dim restoredValues(values.Length - 1) As Single
      Dim sr As New StreamReader(".\Singles.dat")
      Dim temp As String = sr.ReadToEnd()
      Dim tempStrings() As String = temp.Split("|"c)
      For ctr As Integer = 0 To tempStrings.Length - 1
         restoredValues(ctr) = Single.Parse(tempStrings(ctr))   
      Next 

      For ctr As Integer = 0 To values.Length - 1
         Console.WriteLine("{0} {2} {1}", values(ctr), 
                           restoredValues(ctr),
                           If(values(ctr).Equals(restoredValues(ctr)), "=", "<>"))
      Next
   End Sub
End Module

Module Example
   Public Sub Main()
      Dim value1 As Double = 1/3
      Dim sValue2 As Single = 1/3
      Dim value2 As Double = CDbl(sValue2)
      Console.WriteLine("{0} = {1}: {2}", value1, value2, value1.Equals(value2))
   End Sub
End Module

Module Example
   Public Sub Main()
      Dim value1 As Single = .3333333
      Dim value2 As Single = 1/3
      Console.WriteLine("{0:R} = {1:R}: {2}", value1, value2, value1.Equals(value2))
   End Sub
End Module

Module Example
   Public Sub Main()
      Dim value1 As Single = 10.201438
      value1 = CSng(Math.Sqrt(CSng(Math.Pow(value1, 2))))
      Dim value2 As Single = CSng(Math.Pow(value1 * CSng(3.51), 2))
      value2 = CSng(Math.Sqrt(value2) / CSng(3.51))
      Console.WriteLine("{0} = {1}: {2}", 
                        value1, value2, value1.Equals(value2)) 
      Console.WriteLine()
      Console.WriteLine("{0:G9} = {1:G9}", value1, value2) 
   End Sub
End Module

Module Example
   Public Sub Main()
      Dim value1 As Single = .3333333
      Dim value2 As Single = 1/3
      Dim precision As Integer = 7
      value1 = CSng(Math.Round(value1, precision))
      value2 = CSng(Math.Round(value2, precision))
      Console.WriteLine("{0:R} = {1:R}: {2}", value1, value2, value1.Equals(value2))
   End Sub
End Module

Module Example
   Public Sub Main()
      Dim one1 As Single = .1 * 10
      Dim one2 As Single = 0
      For ctr As Integer = 1 To 10
         one2 += CSng(.1)
      Next
      Console.WriteLine("{0:R} = {1:R}: {2}", one1, one2, one1.Equals(one2))
      Console.WriteLine("{0:R} is approximately equal to {1:R}: {2}", 
                        one1, one2, 
                        IsApproximatelyEqual(one1, one2, .000001))   
   End Sub

   Function IsApproximatelyEqual(value1 As Single, value2 As Single, 
                                 epsilon As Single) As Boolean
      ' If they are equal anyway, just return True.
      If value1.Equals(value2) Then Return True
      
      ' Handle NaN, Infinity.
      If Single.IsInfinity(value1) Or Single.IsNaN(value1) Then
         Return value1.Equals(value2)
      Else If Single.IsInfinity(value2) Or Single.IsNaN(value2)
         Return value1.Equals(value2)
      End If
      
      ' Handle zero to avoid division by zero
      Dim divisor As Single = Math.Max(value1, value2)
      If divisor.Equals(0) Then
         divisor = Math.Min(value1, value2)
      End If 
      
      Return Math.Abs(value1 - value2)/divisor <= epsilon           
   End Function
End Module

Module Example
   Public Sub Main()
      Dim value1 As Single = 1.163287e-36
      Dim value2 As Single = 9.164234e-25
      Dim result As Single = value1 * value2
      Console.WriteLine("{0} * {1} = {2:R}", value1, value2, result)
      Console.WriteLine("{0} = 0: {1}", result, result.Equals(0))
   End Sub
End Module

Module Example
   Public Sub Main()
      Dim value1 As Single = 3.065e35
      Dim value2 As Single = 6.9375e32
      Dim result As Single = value1 * value2
      Console.WriteLine("PositiveInfinity: {0}", 
                         Single.IsPositiveInfinity(result))
      Console.WriteLine("NegativeInfinity: {0}", 
                        Single.IsNegativeInfinity(result))
      Console.WriteLine()                  
      value1 = -value1
      result = value1 * value2
      Console.WriteLine("PositiveInfinity: {0}", 
                         Single.IsPositiveInfinity(result))
      Console.WriteLine("NegativeInfinity: {0}", 
                        Single.IsNegativeInfinity(result))
   End Sub
End Module

Module Example
   Public Sub Main()
      Dim values() As Object = { Byte.MinValue, Byte.MaxValue, Decimal.MinValue,
                                 Decimal.MaxValue, Double.MinValue, Double.MaxValue,
                                 Int16.MinValue, Int16.MaxValue, Int32.MinValue,
                                 Int32.MaxValue, Int64.MinValue, Int64.MaxValue,
                                 SByte.MinValue, SByte.MaxValue, UInt16.MinValue,
                                 UInt16.MaxValue, UInt32.MinValue, UInt32.MaxValue,
                                 UInt64.MinValue, UInt64.MaxValue }
      Dim sngValue As Single
      For Each value In values
         If value.GetType() = GetType(Double) Then
            sngValue = CSng(value)
         Else
            sngValue = value
         End If
         Console.WriteLine("{0} ({1}) --> {2:R} ({3})",
                           value, value.GetType().Name,
                           sngValue, sngValue.GetType().Name)
      Next
   End Sub
End Module

Module Example
   Public Sub Main()
      Dim values() As Single = { Single.MinValue, -67890.1234, -12345.6789,
                                 12345.6789, 67890.1234, Single.MaxValue,
                                 Single.NaN, Single.PositiveInfinity,
                                 Single.NegativeInfinity }
      For Each value In values
         Try
             Dim lValue As Long = CLng(value)
             Console.WriteLine("{0} ({1}) --> {2} (0x{2:X16}) ({3})",
                               value, value.GetType().Name,
                               lValue, lValue.GetType().Name)
         Catch e As OverflowException
            Console.WriteLine("Unable to convert {0} to Int64.", value)
         End Try
         Try
             Dim ulValue As UInt64 = CULng(value)
             Console.WriteLine("{0} ({1}) --> {2} (0x{2:X16}) ({3})",
                               value, value.GetType().Name,
                               ulValue, ulValue.GetType().Name)
         Catch e As OverflowException
            Console.WriteLine("Unable to convert {0} to UInt64.", value)
         End Try
         Try
             Dim dValue As Decimal = CDec(value)
             Console.WriteLine("{0} ({1}) --> {2} ({3})",
                               value, value.GetType().Name,
                               dValue, dValue.GetType().Name)
         Catch e As OverflowException
            Console.WriteLine("Unable to convert {0} to Decimal.", value)
         End Try

         Dim dblValue As Double = value
         Console.WriteLine("{0} ({1}) --> {2} ({3})",
                           value, value.GetType().Name,
                           dblValue, dblValue.GetType().Name)
         Console.WriteLine()
      Next
   End Sub
End Module
' The example displays the following output for conversions performed
' in a checked context:
'       Unable to convert -3.402823E+38 to Int64.
'       Unable to convert -3.402823E+38 to UInt64.
'       Unable to convert -3.402823E+38 to Decimal.
'       -3.402823E+38 (Single) --> -3.40282346638529E+38 (Double)
'
'       -67890.13 (Single) --> -67890 (0xFFFFFFFFFFFEF6CE) (Int64)
'       Unable to convert -67890.13 to UInt64.
'       -67890.13 (Single) --> -67890.12 (Decimal)
'       -67890.13 (Single) --> -67890.125 (Double)
'
'       -12345.68 (Single) --> -12346 (0xFFFFFFFFFFFFCFC6) (Int64)
'       Unable to convert -12345.68 to UInt64.
'       -12345.68 (Single) --> -12345.68 (Decimal)
'       -12345.68 (Single) --> -12345.6787109375 (Double)
'
'       12345.68 (Single) --> 12346 (0x000000000000303A) (Int64)
'       12345.68 (Single) --> 12346 (0x000000000000303A) (UInt64)
'       12345.68 (Single) --> 12345.68 (Decimal)
'       12345.68 (Single) --> 12345.6787109375 (Double)
'
'       67890.13 (Single) --> 67890 (0x0000000000010932) (Int64)
'       67890.13 (Single) --> 67890 (0x0000000000010932) (UInt64)
'       67890.13 (Single) --> 67890.12 (Decimal)
'       67890.13 (Single) --> 67890.125 (Double)
'
'       Unable to convert 3.402823E+38 to Int64.
'       Unable to convert 3.402823E+38 to UInt64.
'       Unable to convert 3.402823E+38 to Decimal.
'       3.402823E+38 (Single) --> 3.40282346638529E+38 (Double)
'
'       Unable to convert NaN to Int64.
'       Unable to convert NaN to UInt64.
'       Unable to convert NaN to Decimal.
'       NaN (Single) --> NaN (Double)
'
'       Unable to convert Infinity to Int64.
'       Unable to convert Infinity to UInt64.
'       Unable to convert Infinity to Decimal.
'       Infinity (Single) --> Infinity (Double)
'
'       Unable to convert -Infinity to Int64.
'       Unable to convert -Infinity to UInt64.
'       Unable to convert -Infinity to Decimal.
'       -Infinity (Single) --> -Infinity (Double)
' The example displays the following output for conversions performed
' in an unchecked context:
'       -3.402823E+38 (Single) --> -9223372036854775808 (0x8000000000000000) (Int64)
'       -3.402823E+38 (Single) --> 9223372036854775808 (0x8000000000000000) (UInt64)
'       Unable to convert -3.402823E+38 to Decimal.
'       -3.402823E+38 (Single) --> -3.40282346638529E+38 (Double)
'
'       -67890.13 (Single) --> -67890 (0xFFFFFFFFFFFEF6CE) (Int64)
'       -67890.13 (Single) --> 18446744073709483726 (0xFFFFFFFFFFFEF6CE) (UInt64)
'       -67890.13 (Single) --> -67890.12 (Decimal)
'       -67890.13 (Single) --> -67890.125 (Double)
'
'       -12345.68 (Single) --> -12346 (0xFFFFFFFFFFFFCFC6) (Int64)
'       -12345.68 (Single) --> 18446744073709539270 (0xFFFFFFFFFFFFCFC6) (UInt64)
'       -12345.68 (Single) --> -12345.68 (Decimal)
'       -12345.68 (Single) --> -12345.6787109375 (Double)
'
'       12345.68 (Single) --> 12346 (0x000000000000303A) (Int64)
'       12345.68 (Single) --> 12346 (0x000000000000303A) (UInt64)
'       12345.68 (Single) --> 12345.68 (Decimal)
'       12345.68 (Single) --> 12345.6787109375 (Double)
'
'       67890.13 (Single) --> 67890 (0x0000000000010932) (Int64)
'       67890.13 (Single) --> 67890 (0x0000000000010932) (UInt64)
'       67890.13 (Single) --> 67890.12 (Decimal)
'       67890.13 (Single) --> 67890.125 (Double)
'
'       3.402823E+38 (Single) --> -9223372036854775808 (0x8000000000000000) (Int64)
'       3.402823E+38 (Single) --> 0 (0x0000000000000000) (UInt64)
'       Unable to convert 3.402823E+38 to Decimal.
'       3.402823E+38 (Single) --> 3.40282346638529E+38 (Double)
'
'       NaN (Single) --> -9223372036854775808 (0x8000000000000000) (Int64)
'       NaN (Single) --> 0 (0x0000000000000000) (UInt64)
'       Unable to convert NaN to Decimal.
'       NaN (Single) --> NaN (Double)
'
'       Infinity (Single) --> -9223372036854775808 (0x8000000000000000) (Int64)
'       Infinity (Single) --> 0 (0x0000000000000000) (UInt64)
'       Unable to convert Infinity to Decimal.
'       Infinity (Single) --> Infinity (Double)
'
'       -Infinity (Single) --> -9223372036854775808 (0x8000000000000000) (Int64)
'       -Infinity (Single) --> 9223372036854775808 (0x8000000000000000) (UInt64)
'       Unable to convert -Infinity to Decimal.
'       -Infinity (Single) --> -Infinity (Double)