IList<ElementId> categories = new List<ElementId>();

#1

private static string GetGreetingMessage(string name, double salary)
{
	string a;
	string b;
	a = ("Hello, ");
	b = (", your salary is ");
	a += name;
	a += b;
	a += Math.Ceiling(salary);
    return (string) a;
}

#2

private static string GetGreetingMessage(string name, double salary)
{
    return string.Format("Hello, {0}, your salary is {1}", name, Math.Ceiling(salary));
}