VB.Net Tutorial/Data Type/Double — различия между версиями

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Текущая версия на 15:54, 26 мая 2010

Convert Double to Integer

<source lang="vbnet">Module Module1

   Sub Main()
       Dim dblValue As Double
       Dim intValue As Integer
       dblValue = 1.2345678
       intValue = dblValue
       Console.WriteLine(intValue)
   End Sub

End Module</source>

1

Declare Double type variable and assign value

<source lang="vbnet">Module Module1

   Sub Main()
       Dim EmployeeName As String
       Dim EmployeePhoneNumber As String
       Dim EmployeeSalary As Double
       Dim NumberOfEmployees As Integer
       EmployeeName = "James Bond"
       EmployeePhoneNumber = "555-1212"
       EmployeeSalary = 45.0
       NumberOfEmployees = 1
       Console.WriteLine("Number of employees: " & NumberOfEmployees)
       Console.WriteLine("Employee name: " & EmployeeName)
       Console.WriteLine("Employee phone number: " & EmployeePhoneNumber)
       Console.WriteLine("Employee salary: " & EmployeeSalary)
   End Sub

End Module</source>

Number of employees: 1
Employee name: James Bond
Employee phone number: 555-1212
Employee salary: 45

Define and loop through double value array

<source lang="vbnet">Module Tester

   Sub Main()
       Dim Values() As Integer = {100, 200, 300, 400, 500}
       Dim MyValues(5) As Integer
       Dim Prices() As Double = {25.5, 4.95, 33.4}
       Dim I As Integer
       For I = 0 To 4
           Console.Write(Values(I) & " ")
       Next
       Console.WriteLine()
       For I = 0 To Prices.GetUpperBound(0)
           Console.Write(Prices(I) & " ")
       Next
   End Sub

End Module</source>

100 200 300 400 500
25.5 4.95 33.4

Define double and output its value

<source lang="vbnet">public class Test

  public Shared Sub Main
       Dim I As Integer = 2
       I *= 5
       Console.WriteLine(I)
   
       Dim D As Double = I / 3
       Console.WriteLine(D)
  End Sub

End class</source>

10
3.33333333333333

Double.IsNaN()

<source lang="vbnet">Imports System Module MyModule

 Sub Main()
   If (Double.IsNaN("1.2")) Then
     Console.WriteLine("Not a Number.")
   End If
 End Sub

End Module</source>

Double.IsNegativeInfinity()

<source lang="vbnet">Imports System Module MyModule

 Sub Main()
   If (Double.IsNegativeInfinity("0.0000000000000001")) Then
       Console.WriteLine("Negative infinity.")
   End If
 End Sub

End Module</source>

Double.IsPositiveInfinity()

<source lang="vbnet">Imports System Module MyModule

 Sub Main()
   If (Double.IsPositiveInfinity("999999999999999999999999999999999")) Then
     Console.WriteLine("Positive infinity.")
   End If
 End Sub

End Module</source>

Get Epsilon from Double

<source lang="vbnet">public class Test

  public Shared Sub Main
       Dim D As Double
   
       D = 5
       Console.WriteLine(D.Epsilon)
  End Sub

End class</source>

4.94065645841247E-324

Parse Double

<source lang="vbnet">Imports System Module MyModule

 Sub Main()
   Dim num As Double = Double.Parse("12.12")
   Dim denom As Double = Double.Parse("2.2")
   Dim res As Double = num / denom
   Console.WriteLine(res)
 End Sub

End Module</source>

5.50909090909091

Parse double value

<source lang="vbnet">Public Class Tester

   Public Shared Sub Main
       Dim doubleParse As Double = Double.Parse("3.1416")
       Console.WriteLine(doubleParse)
   End Sub

End Class</source>

3.1416

Read Double value from Keyboard

<source lang="vbnet">Module Module1

   Sub Main()
       Dim Salary As Double
       Console.Write("Salary: ")
       Salary = Console.ReadLine()
       Console.WriteLine(Salary)
   End Sub

End Module</source>

Salary: 123
123