自定义类型强制装换

----------------------------------------------------------------------Currency.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace ConsoleApplication4
{
    //类和结构相似
    public struct Currency
    {
        private uint dollars; //元
        private ushort cents; //分
        public Currency(uint i, ushort s)//初始化构造函数
        {
            this.dollars = i;
            this.cents = s;
        }
        public override string ToString()
        {
            return string.Format("{0}.{1,2:00}", dollars, cents);
        }
        //看情况选择是显示装换还是隐式转换，（uint和ushort都可以隐式转换为float）
        //重载运算符必须使用public static 
        //implicit 隐式转换
        //把Currency对象隐式转换为float类型
        public static implicit operator float(Currency c)
        {
            return c.dollars + c.cents / 100.0f;
        }
        //explicit为显式转换
        //把float对象显式转换为Currency类型
        public static explicit operator Currency(float f)
        {
            checked//溢出则抛出异常
            {
                uint i = (uint)f;
                ushort s = Convert.ToUInt16((f - i) * 100);
                return new Currency(i, s);
            }
        }
    }
}

----------------------------------------------------------------------主程序

 Currency c = new Currency(50, 35);
            float f = (float)(c);
            c = (Currency)f;
            Console.WriteLine(c.ToString());
            Console.ReadKey();