运算符重载为主要类型 [英] operator overloading for primative types

问题描述

似乎C ++不允许为主要的

类型重载运算符，例如int，double。我想知道它是否真的有没有

一些走动？


谢谢，

彭


#include< iostream>

#include< complex>


命名空间我的

{

int operator /（int x，int y）{

if（x> 0）

返回x / y;

其他

返回x / y - 1;

}


void test（int x， int y）{

std :: cout<< x<< " /" << y<< " " << x / y<< std :: endl;

}


}


int main（）{

my :: test（10,3）;

my :: test（-10,3）;

my :: test（10，-3）;

my :: test（-10，-3）;

}

解决方案

Pe*******@gmail.com 写道：

似乎C ++不允许为主要的

类型重载运算符，例如int，double。我想知道它是否是

这是真的。参见条款[13.3.1.2/1]

如果表达式中的运算符的操作数没有类型为

或枚举，则假定运算符为是一个内置的操作员和

根据第5条解释。

或有一些绕行？

我不知道透明的任何工作。您必须装备您的操作数

，以便其中至少有一个不是内置类型。

最佳


Kai-Uwe Bux

Pe ******* @ gmail .com 写道：

似乎C ++不允许重载运算符为主要

类型，例如int，double。我想知道它是否真的有没有

一些走动？

幸运的是你不能这样做会产生不会像其他人期望的那样行事的代码，这是一个难以维持的噩梦。


如果你想要一个有特殊行为的类型，用适当的操作符将它包装在一个类中。


-

Ian Collins。

9月26日晚上10:51，Ian Collins< ian-n ... @ hotmail.comwrote：

PengYu。 .. @ gmail.com写道：

似乎C ++不允许重载运算符为主要的

类型，例如int，double。我想知道它是否真的还是有一些走动？

幸运的是，你不能这样做会产生一些代码，这些代码不会像其他人所希望的那样表现出来。噩梦要维持。

我同意。有些人提倡类似的东西应该通过引入std :: intrusive :: list类型来完成

。我认为最好让它变得更好 -
http ：//tinyurl.com/2q5p34

Brian Wood

Ebenezer Enterprises
www.webebenezer.net

Hi,

It seems that C++ does not allow overloading operators for primative
types, e.g. int, double. I''m wondering whether it is ture or there is
some walk-around?

Thanks,
Peng

#include <iostream>
#include <complex>

namespace my
{
int operator/(int x, int y) {
if(x>0)
return x/y;
else
return x/y - 1;
}

void test(int x, int y) {
std::cout << x << "/" << y << " " << x/y << std::endl;
}

}

int main() {
my::test(10, 3);
my::test(-10, 3);
my::test(10, -3);
my::test(-10, -3);
}

解决方案

Pe*******@gmail.com wrote:

Hi,

It seems that C++ does not allow overloading operators for primative
types, e.g. int, double. I''m wondering whether it is ture

It is true. See clause [13.3.1.2/1]
If no operand of an operator in an expression has a type that is a class
or an enumeration, the operator is assumed to be a built-in operator and
interpreted according to clause 5.

or there is some walk-around?

I don''t know of any that work transparently. You have to rig your operands
so that at least one of them is not of built-in type.
Best

Kai-Uwe Bux

Pe*******@gmail.com wrote:

Hi,

It seems that C++ does not allow overloading operators for primative
types, e.g. int, double. I''m wondering whether it is ture or there is
some walk-around?

Luckily you can''t, doing so would produce code that doesn''t behave as
others would expect it to, a nightmare to maintain.

If you want a type with specialised behavior, wrap it in a class with
the appropriate operators.

--
Ian Collins.

On Sep 26, 10:51 pm, Ian Collins <[e-mail]:

[e-mail] wrote:

Hi,

It seems that C++ does not allow overloading operators for primative
types, e.g. int, double. I''m wondering whether it is ture or there is
some walk-around?

Luckily you can''t, doing so would produce code that doesn''t behave as
others would expect it to, a nightmare to maintain.

I agree. Some people are advocating something similar should be done
by introducing a std::intrusive::list type. I think it would be
better to make it ilist -
http://tinyurl.com/2q5p34
Brian Wood
Ebenezer Enterprises
www.webebenezer.net

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