从指定数量的整数中确定素数VB控制台App

Module Module1
    Sub Main()
        Dim num As Integer
        Console.WriteLine("请输入一个整数：")
        num = Console.ReadLine()

        Dim isPrime As Boolean = True
        If num <= 1 Then
            isPrime = False
        Else
            For i As Integer = 2 To Math.Sqrt(num)
                If num Mod i = 0 Then
                    isPrime = False
                    Exit For
                End If
            Next
        End If

        If isPrime Then
            Console.WriteLine(num & " 是素数。")
        Else
            Console.WriteLine(num & " 不是素数。")
        End If

        Console.ReadLine()
    End Sub
End Module