“带接口的C ++” （CUJ第22卷第9期） [英] "C++ with Interfaces" (article in CUJ vol 22 no 9)
问题描述
有趣的文章。然而，它从一个例子开始，我发现
相当误导。我希望作者（克里斯托弗迪金斯）如果我在文章中发表引文，就不会想到。我知道他可能会阅读或者
甚至写给clc ++。有时候。
克里斯托弗给出了这个[伪]代码（是的，它是'不是C ++）：
界面IFuBar {
合约：
无效FuBar（）;
};
struct BaseFuBar {
void FuBar（）{std :: cout<< " BaseFuBar英寸; }
};
struct DerivedFuBar：public BaseFuBar {
void FuBar（）{std :: cout<< " DerivedFuBar英寸; }
};
main（）{
DerivedFuBar d;
BaseFuBar& b = d;
IFuBar i = b;
i.FuBar（）; //输出BaseFuBar
}
然后声称标准C ++中接近此设计的常用方法
是："
struct AbcFuBar {
虚拟无效FuBar（）= 0;
};
// vb：缺少#include< iostream>
struct BaseFuBar：public AbcFuBar {// vb：public是不必要的
void FuBar（）{std :: cout<< " BaseFuBar英寸; }
};
struct DerivedFuBar：public BaseFuBar {
void FuBar（）{std :: cout<< " DerivedFuBar英寸; }
};
main（）{// vb：哪里是''int''？
DerivedFuBar d;
BaseFuBar& b = d; /// ************************
AbcFuBar& a = b;
a.FuBar（）; //输出DerivedFuBar
}
嗯，简单的''public''缺失，缺少< iostream>和
absense''main''返回值类型除外，代码似乎合乎逻辑，是吗？
我通过更改标有
星号，所需的行为可以__rectly_实现：
BaseFuBar b = d;
与作者所暗示的相反。
现在，我在想：我是否应该看完这篇文章的其余部分
看到了这个和
main（）{
...
在一个所谓的_standard_ C ++程序中？
Christopher是Heron的开发者，另一种语言。我想知道，
我们真的需要另一种语言开发，因为有人没有足够的学习现有的语言吗？不，那不可能......
无论如何...
Victor
Interesting article. However, it starts with an example which I find
rather misleading. I hope the author (Christopher Diggins) wouldn''t
mind if I post a quote from the article. I know he probably reads or
even writes to c.l.c++.m sometimes.
Christopher gives this [pseudo-]code (yes, it''s not C++):
interface IFuBar {
contract:
void FuBar();
};
struct BaseFuBar {
void FuBar() { std::cout << "BaseFuBar"; }
};
struct DerivedFuBar : public BaseFuBar {
void FuBar() { std::cout << "DerivedFuBar"; }
};
main() {
DerivedFuBar d;
BaseFuBar& b = d;
IFuBar i = b;
i.FuBar(); // outputs BaseFuBar
}
and then claims that "the common way to approximate this design
in standard C++ is:"
struct AbcFuBar {
virtual void FuBar() = 0;
};
// vb: missing #include <iostream>
struct BaseFuBar : public AbcFuBar { // vb: public is unnecessary
void FuBar() { std::cout << "BaseFuBar"; }
};
struct DerivedFuBar : public BaseFuBar {
void FuBar() { std::cout << "DerivedFuBar"; }
};
main() { // vb: where is ''int''?
DerivedFuBar d;
BaseFuBar& b = d; /// ************************
AbcFuBar& a = b;
a.FuBar(); // output DerivedFuBar
}
Well, simple superfluosity of ''public'', the missing <iostream>, and the
absense of ''main'' return value type aside, the code seems logical, yes?
I submit that by changing a single character on the line marked with
asterisks, the desired behaviour can be _correctly_ implemented:
BaseFuBar b = d;
contrary to what the author implies.
Now, I am thinking: should I really read the rest of the article after
seeing that and
main() {
...
in a supposedly _standard_ C++ program?
Christopher is a developer of Heron, another language. I am wondering,
do we really need another language developed because somebody hasn''t got
around to learning existing ones well enough? Nah, that can''t be it...
Anyway...
Victor
推荐答案
* Victor Bazarov：
* Victor Bazarov:
struct AbcFuBar {
virtual void FuBar（）= 0;
}; <
// vb：缺少#include< iostream>
struct BaseFuBar：public AbcFuBar {// vb：public是不必要的
void FuBar（）{std： ：cout<< " BaseFuBar英寸; }
};
struct DerivedFuBar：public BaseFuBar {
void FuBar（）{std :: cout<< " DerivedFuBar英寸; }
};
main（）{// vb：哪里是''int''？
DerivedFuBar d;
BaseFuBar& b = d; /// ************************
AbcFuBar& a = b;
a.FuBar（）; //输出DerivedFuBar
}
嗯，简单的''public''缺失，缺少< iostream>，以及''main''返回值的缺失除了类型之外，代码似乎合乎逻辑，是吗？
我通过更改标有
星号的行上的单个字符来提交，可以__rectly_实现所需的行为：
BaseFuBar b = d;
与作者所暗示的相反。
struct AbcFuBar {
virtual void FuBar() = 0;
};
// vb: missing #include <iostream>
struct BaseFuBar : public AbcFuBar { // vb: public is unnecessary
void FuBar() { std::cout << "BaseFuBar"; }
};
struct DerivedFuBar : public BaseFuBar {
void FuBar() { std::cout << "DerivedFuBar"; }
};
main() { // vb: where is ''int''?
DerivedFuBar d;
BaseFuBar& b = d; /// ************************
AbcFuBar& a = b;
a.FuBar(); // output DerivedFuBar
}
Well, simple superfluosity of ''public'', the missing <iostream>, and the
absense of ''main'' return value type aside, the code seems logical, yes?
I submit that by changing a single character on the line marked with
asterisks, the desired behaviour can be _correctly_ implemented:
BaseFuBar b = d;
contrary to what the author implies.
Haven不读这篇文章（你有吗？一个链接？），但是：
期望的行为是什么？
根据你所写的内容来判断是否接到BaseFuBar的电话:: FuBar？
这很容易实现，如你所示;还有其他方法。
顺便说一句。你在clc ++中发帖，而不是clc ++ m ... ;-)
-
答：因为它弄乱了订单人们通常会阅读文字。
问：为什么这么糟糕？
A：热门帖子。
问：什么是usenet和电子邮件中最烦人的事情是？
Haven''t read the article (do you have a link?), but:
What is the desired behavior?
Judging from what you write it is to get a call of BaseFuBar::FuBar?
That''s easy to achieve as you''ve shown; there are also other ways.
Btw. you''re posting in clc++, not clc++m... ;-)
--
A: Because it messes up the order in which people normally read text.
Q: Why is it such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?
" Alf P. Steinbach"写道：
[...]
"Alf P. Steinbach" wrote:
[...]
期望的行为是什么？
使用Warp 9.9999进行虚拟调度速度和零空间开销。
中尉指挥官数据充满了这些东西。
问候，
亚历山大。
Virtual dispatch with Warp 9.9999 velocity and zero space overhead.
Lieutenant Commander Data is full of such things.
regards,
alexander.
Alf P. Steinbach写道：
Alf P. Steinbach wrote:
* Victor Bazarov：
* Victor Bazarov:
struct AbcFuBar {
virtual void FuBar（）= 0;
};
// vb：缺少#include< iostream>
struct BaseFuBar：public AbcFuBar { // vb：public是不必要的
void FuBar（）{std :: cout<< " BaseFuBar英寸; }
};
struct DerivedFuBar：public BaseFuBar {
void FuBar（）{std :: cout<< " DerivedFuBar英寸; }
};
main（）{// vb：哪里是''int''？
DerivedFuBar d;
BaseFuBar& b = d; /// ************************
AbcFuBar& a = b;
a.FuBar（）; //输出DerivedFuBar
}
嗯，简单的''public''缺失，缺少< iostream>，以及''main''返回值的缺失除了类型之外，代码似乎合乎逻辑，是吗？
我通过更改标有
星号的行上的单个字符来提交，可以__rectly_实现所需的行为：
BaseFuBar b = d;
与作者所暗示的相反。
Haven没有读过这篇文章（你有链接吗？），但是：
struct AbcFuBar {
virtual void FuBar() = 0;
};
// vb: missing #include <iostream>
struct BaseFuBar : public AbcFuBar { // vb: public is unnecessary
void FuBar() { std::cout << "BaseFuBar"; }
};
struct DerivedFuBar : public BaseFuBar {
void FuBar() { std::cout << "DerivedFuBar"; }
};
main() { // vb: where is ''int''?
DerivedFuBar d;
BaseFuBar& b = d; /// ************************
AbcFuBar& a = b;
a.FuBar(); // output DerivedFuBar
}
Well, simple superfluosity of ''public'', the missing <iostream>, and the
absense of ''main'' return value type aside, the code seems logical, yes?
I submit that by changing a single character on the line marked with
asterisks, the desired behaviour can be _correctly_ implemented:
BaseFuBar b = d;
contrary to what the author implies.
Haven''t read the article (do you have a link?), but:
不，我没有链接。我刚收到杂志的副本。
期望的行为是什么？
正如我从伪代码中所理解的那样，它要使BaseFuBar子对象
来做它的事情，而不是DerivedFuBar。
根据你所写的内容来判断是否接到了BaseFuBar :: FuBar的电话？
我是这么认为的。
这很容易实现，如你所示;还有其他方法。
您应该发布您的版本。
顺便说一句。你发布的是clc ++，而不是clc ++ m ...; - ）
No, I don''t have a link. I just have my copy of the magazine.
What is the desired behavior?
As I understood from the pseudo-code it''s to make the BaseFuBar subobject
to do its thing, but not the DerivedFuBar.
Judging from what you write it is to get a call of BaseFuBar::FuBar?
I thought so.
That''s easy to achieve as you''ve shown; there are also other ways.
You should post your versions.
Btw. you''re posting in clc++, not clc++m... ;-)
我知道。我很少在c.l.c ++。中发帖。太符合我的口味了。
V
I know. I rarely post in c.l.c++.m. Too ''m'' for my taste.
V
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