如何创建一个只显式转换为int的类？ [英] How to create a class that casting to int explicitly only?
问题描述
我有一个类数据如下
class Data {
... 。
};
我知道如果我想将它隐式地转换为int我应该像
一样写下：
类数据{
....
public：
operator int（）{.. 。};
};
所以，我可以使用类似的课程，
数据d（1234 ）;
int a = d;
然而，我真正想要的是类Data的用户已明确
cast它是int。
也就是说，用户应该编写如下代码：
int a =（int）d;
除了：
int a = d;
如何才能明确地将强制转换为int ？
谢谢。
王涛
Hi,
I have a class Data as following
class Data{
....
};
I know if I want to cast it to int implicitly I should write like
following:
class Data{
....
public:
operator int() {...};
};
So, I can use the class like,
Data d(1234);
int a = d;
However, what I really want is that user of class Data have explicitly
cast it to int.
that is, user should write the code like:
int a = (int) d;
other than:
int a = d;
How can I make the cast to int explicitly only?
Thanks.
Tao Wang
推荐答案
7月30日，10：18，Tao Wang< Dancef ... @ gmail.comwrote：
On 30 Jul, 10:18, Tao Wang <Dancef...@gmail.comwrote:
我有一个类数据如下
class Data {
...
};
我知道如果我想将它隐式地转换为int我应该写成
以下：
class Data {
...
public：
* * operator int（）{...};
};
所以，我可以使用类似的课程，
数据d（1234）;
int a = d;
但是，我真正想要的是，类Data的用户明确地将
投射到了int。
也就是说，用户应该编写如下代码：
int a =（int）d;
除了：
int a = d;
如何才能明确地将强制转换为int？
Hi,
I have a class Data as following
class Data{
...
};
I know if I want to cast it to int implicitly I should write like
following:
class Data{
...
public:
* *operator int() {...};
};
So, I can use the class like,
Data d(1234);
int a = d;
However, what I really want is that user of class Data have explicitly
cast it to int.
that is, user should write the code like:
int a = (int) d;
other than:
int a = d;
How can I make the cast to int explicitly only?
这样做你想要的吗？
class Data
{
public：
显式数据（int）;
};
-
Nick Keighley
does this do what you want?
class Data
{
public:
explicit Data(int);
};
--
Nick Keighley
文章
< e2 ****************** ****************@a2g2000prm.g ooglegroups.com> ;,
Tao Wang< Da ******* @ gmail.comwrote：
In article
<e2**********************************@a2g2000prm.g ooglegroups.com>,
Tao Wang <Da*******@gmail.comwrote:
...
class Data {
...
public ：
operator int（）{...};
};
所以，我可以使用类，
数据d（1234）;
int a = d;
然而，我真正想要的是类Data的用户明确地将
强制转换为int。
也就是说，用户应该编写如下代码：
int a =（int）d;
除了：
int a = d;
如何才能明确地将强制转换为int？
...
class Data{
...
public:
operator int() {...};
};
So, I can use the class like,
Data d(1234);
int a = d;
However, what I really want is that user of class Data have explicitly
cast it to int.
that is, user should write the code like:
int a = (int) d;
other than:
int a = d;
How can I make the cast to int explicitly only?
class Data {
....
public：
int to_int（）{...};
};
数据d（1234）;
int a =（int ）d; //错误
int b = d.to_int（）; // OK
class Data{
....
public:
int to_int() {...};
};
Data d(1234);
int a = (int) d; // error
int b = d.to_int(); // OK
7月30日上午11：28 *上午，Nick Keighley< nick_keighley_nos ... @ hotmail.com>
写道：
On Jul 30, 11:28*am, Nick Keighley <nick_keighley_nos...@hotmail.com>
wrote:
>
这样做你想要的吗？
class Data
{
* * public：
* * * *显式数据（int）;
} ;
>
does this do what you want?
class Data
{
* * public:
* * * * explicit Data(int);
};
1）我不确定你可以向铸造操作员添加显式。
2）如果确实有效，它将会仍然不会做他想要的......
我认为blargg是对的......
1 )I''m not sure You can add explicit to a casting operator.
2) If it does work it will still wont do what he wants...
I think blargg is right...
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