(1) 兩者都是按地址傳遞的，使用後都將改變原來的數值

(5) ref是有進有出，out是僅僅出不進

        string outString = "This is the original outString";
        Console.WriteLine(outString);
        outMethod(out outString);
        Console.WriteLine(outString);

        string refString = "This is the original ref string";
        Console.WriteLine(refString);
        refMethod(ref refString);
        Console.WriteLine(refString);