Question

How to check if a string is a positive number, negative number or not a number in VB.NET

Answer 1

Imports System

Public Class Program
    Public Shared Function PositiveOrNegative(ByVal s As String) As String
        Try
            Dim n As Double = Double.Parse(s)

            If n < 0 Then
                Return "negative"
            Else
                Return "positive"
            End If

        Catch ex As Exception
            Return "not a number"
        End Try
    End Function

    Public Shared Sub Main(ByVal args As String())
        Dim s As String = "84593"
        Console.WriteLine(PositiveOrNegative(s))
		
        s = "-15"
        Console.WriteLine(PositiveOrNegative(s))
		
        s = "18W"
        Console.WriteLine(PositiveOrNegative(s))
    End Sub
End Class



' run:
'
' positive
' negative
' not a number
'

 

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