VB.NET

VB.NET was introduced in 2001 as a successor to Visual Basic. I had had no prior experience with anything .NET, and was expecting a bit of a learning curve, but it took me five minutes to write this version of Euler1 - it looks just like VB6 of yore:

' Euler1 in VB.NET
Imports System

Public Module modmain

    Function Euler1 (size As Integer) As Integer
        For i As Integer = 1 to size
            If (i mod 3 = 0 or i mod 5 = 0) Then
                Euler1 = Euler1 + i
            End If
        Next
    End Function

    Sub Main()
        Console.WriteLine (Euler1(999))
    End Sub

End Module

To compile this code, I simply used Yum to install mono-basic. Then, I compiled my code with vbnc. I couldn't find how to execute the resultant .exe, so I guessed and tried to execute it the same way I ran my C# code - with the mono runtime. Success!

$ vbnc euler1.vb
$ mono euler1.exe
233168
$