斗士狗 2012-05-25 02:39 采纳率: 0%
浏览 378
已采纳

在 c + + 11中'typedef'和'using'之间有什么区别?

I know that in C++11 we can now use using to write type alias, like typedefs:

typedef int MyInt;

Is, from what I understand, equivalent to:

using MyInt = int;

And that new syntax emerged from the effort to have a way to express "template typedef":

template< class T > using MyType = AnotherType< T, MyAllocatorType >;

But, with the first two non-template examples, are there any other subtle differences in the standard? For example, typedefs do aliasing in a "weak" way. That is it does not create a new type but only a new name (conversions are implicit between those names).

Is it the same with using or does it generate a new type? Are there any differences?

转载于:https://stackoverflow.com/questions/10747810/what-is-the-difference-between-typedef-and-using-in-c11

  • 写回答

4条回答 默认 最新

  • 北城已荒凉 2012-05-25 03:16
    关注

    They are equivalent, from the standard (emphasis mine) (7.1.3.2):

    A typedef-name can also be introduced by an alias-declaration. The identifier following the using keyword becomes a typedef-name and the optional attribute-specifier-seq following the identifier appertains to that typedef-name. It has the same semantics as if it were introduced by the typedef specifier. In particular, it does not define a new type and it shall not appear in the type-id.

    本回答被题主选为最佳回答 , 对您是否有帮助呢?
    评论
查看更多回答(3条)

报告相同问题?

悬赏问题

  • ¥15 seatunnel-web使用SQL组件时候后台报错,无法找到表格
  • ¥15 fpga自动售货机数码管(相关搜索:数字时钟)
  • ¥15 用前端向数据库插入数据,通过debug发现数据能走到后端,但是放行之后就会提示错误
  • ¥30 3天&7天&&15天&销量如何统计同一行
  • ¥30 帮我写一段可以读取LD2450数据并计算距离的Arduino代码
  • ¥15 C#调用python代码(python带有库)
  • ¥15 飞机曲面部件如机翼,壁板等具体的孔位模型
  • ¥15 vs2019中数据导出问题
  • ¥20 云服务Linux系统TCP-MSS值修改?
  • ¥20 关于#单片机#的问题:项目:使用模拟iic与ov2640通讯环境:F407问题:读取的ID号总是0xff,自己调了调发现在读从机数据时,SDA线上并未有信号变化(语言-c语言)