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博客园 - Goodspeed

几种常见的函数 Caesar cipher 遗传算法之背包问题 Transport scheme NOT recognized: [stomp] error running git Canvas 旋转的图片 canvas时钟 火箭起飞 让图标转起来 Tomcat启动脚本 Task中的异常处理 Parallel的陷阱 用Task代替TheadPool 使用ThreadPool代替Thread 正确停止线程 线程同步中使用信号量AutoResetEvent 异步和多线程的区别 C#和.NET Framework的关系 为什么泛型不支持协变性?
可空值类型与值类型这间的转换
Goodspeed · 2014-06-29 · via 博客园 - Goodspeed
int s = 5;
int? s_null;
long t;
long? t_null;

t = s; //隐式转换 S -> T
s = (int)t; //显示转换 T -> S

s_null = s; //隐式转换 S -> S?
s = (int)s_null; //显示转换 S? -> T

t_null = s_null; //隐式转换 S? -> T?
s_null = (int?)t_null; //显示转换 T? -> S?

t_null = s; //隐式转换 S -> T?
s = (int)t_null; //显示转换 T? -> S