using System;

public class Program

{

    public static void Test(Func<string,string> f) {

        Console.WriteLine( f(@".") );

        Console.WriteLine( f(@" .") );

        Console.WriteLine( f(@"/") );

        Console.WriteLine( f(@"\") );

        Console.WriteLine( f(@"/\") );

        Console.WriteLine( f(@"\/") );

    }

    public static void Main()

    {

        Func<string,string> fn = s=>s[0]<47?' '+s:s+(s.EndsWith("/")?'\\':'/');

​

        Test(fn);       

    }

}