9 习惯重载运算符

    class Program
    {
        public static void Main(string[] args)
        {
            Salary s1 = new Salary() { RMB = 1 };
            Salary s2 = new Salary() { RMB = 2 };
            Salary total = s1 + s2;
        }
    }

    class Salary
    {
        public int RMB { get; set; }
        public static Salary operator +(Salary s1, Salary s2)
        {
            s2.RMB += s1.RMB;
            return s2;
        }
    }