VB.Net Tutorial/Data Type/Single

Материал из VB Эксперт
Версия от 12:54, 26 мая 2010; Admin (обсуждение | вклад) (1 версия)
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Calcuate Single

Public Class Tester
    Public Shared Sub Main
        Dim magnitude As Single
        Dim radians As Single
        magnitude = CSng(Math.Sqrt(100 ^ 2 + 120 ^ 2))
        radians = CSng(Math.Atan2(100, 123))

        Console.WriteLine(magnitude)
        Console.WriteLine(radians)
        
    End Sub
End Class
156.205
0.6826226

Calculation with Single

public class Test
   public Shared Sub Main
        Dim Amount As Single
        Dim Discount As Single
        Dim DiscAmount As Single
        Amount = 24500
        Discount = 0.35
        DiscAmount = Amount * (1 - Discount)
        Console.WriteLine("Your price is: $" & DiscAmount)
   End Sub
End class
Your price is: $15925

Cast Integer to Short, Double to Single

Module Module1
    Sub Main()
        Dim BigInteger As Integer = 10000
        Dim LittleInteger As Short
        Dim BigFloat As Double = 0.123456789
        Dim LittleFloat As Single
        LittleInteger = BigInteger
        LittleFloat = BigFloat

        Console.WriteLine(LittleInteger)
        Console.WriteLine(LittleFloat)
    End Sub
End Module
10000
0.1234568

Get Epsilon from Single

public class Test
   public Shared Sub Main
      Console.WriteLine(Single.Epsilon)
   End Sub
End class
1.401298E-45

Pass Single by value and by reference to a Sub

public class Test
   public Shared Sub Main
        Dim value As Single
        value = 10
        DoubleItByVal(value)
        Console.WriteLine(value)
        value = 10
        DoubleItByRef(value)
        Console.WriteLine(value)
   End Sub
    Shared Sub DoubleItByVal(ByVal X As Single)
        X *= 2
    End Sub
    Shared Sub DoubleItByRef(ByRef X As Single)
        X *= 2
    End Sub
End class
10
20

Precision Error

Module Module1
    Sub Main()
        Dim A As Single
        "Dim A As Double
        For A = 0.01 To 0.1 Step 0.01
            If (A = 0.05) Then
                Console.WriteLine("Reached 0.05")
            End If
        Next
        Console.WriteLine("Done with loop")
    End Sub
End Module
Done with loop

Show difference precision of Single and Double

Module Module1
    Sub Main()
        Dim A As Single = 0.123456789012345
        Dim B As Double = 0.123456789012345
        Console.WriteLine("Single: " & A)
        Console.WriteLine("Double: " & B)
    End Sub
End Module
Single: 0.1234568
Double: 0.123456789012345

Single Double MaxValue and Memory Size

Public Class Tester
    Public Shared Sub Main
    
        Dim result As New System.Text.StringBuilder
        Dim maxSingle As Single = Single.MaxValue
        Dim maxDouble As Double = Double.MaxValue
        Dim sizeOfSingle As Integer = Runtime.InteropServices.Marshal.SizeOf(maxSingle.GetType)
        Dim sizeOfDouble As Integer = Runtime.InteropServices.Marshal.SizeOf(maxDouble.GetType)
        result.Append("Memory size of a Single (bytes): ")
        result.AppendLine(sizeOfSingle)
        result.Append("Maximum value of a Single: ")
        result.AppendLine(maxSingle)
        result.AppendLine()
        result.Append("Memory size of a Double (bytes): ")
        result.AppendLine(sizeOfDouble)
        result.Append("Maximum value of a Double: ")
        result.AppendLine(maxDouble)
        Console.WriteLine(result.ToString())
     End Sub
End Class
Memory size of a Single (bytes): 4
Maximum value of a Single: 3.402823E+38
Memory size of a Double (bytes): 8
Maximum value of a Double: 1.79769313486232E+308