关于继承的愚蠢问题 [英] silly question about inheritance
问题描述
假设这种情况：
class primitive
{
virtual void IsPointInside（）= NULL;
};
class sphere：public primitive
{...};
class tetrahedron：public primitive
{...};
std :: vector< sphere> v_sphere;
std :: vector< tetrahedron> v_tetrahedron;
//我可以这样做：
std :: vector< primitive *> v_pPrimitives;
for（i = v_sphere.begin; i！= v_sphere.end（）; ++ i）
v_pPrimitives.push_back（& * i）; < br $>
....
//并调用v_pPrimitives [i] .IsPointInside（）; ??
< head scratch>
我不能在一个阵列中存储不同的类型，但我可以存储它们的
指针，没有！？
-
-Gernot
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推荐答案
" Gernot Frisch" < Me@Privacy.net>在消息中写道
新闻：2u ************* @ uni-berlin.de ...
"Gernot Frisch" <Me@Privacy.net> wrote in message
news:2u*************@uni-berlin.de...
假设这种情况：
类原语
{void void IsPointInside（）= NULL;
NULL不保证为0，所以
virtual void IsPointInside（）= 0;
};
类球体：公共原语
{...};
类四面体：公共原语
{...};
标准:: vector< sphere> v_sphere;
std :: vector< tetrahedron> v_tetrahedron;
//我可以这样做：
std :: vector< primitive *> v_pPrimitives;
for（i = v_sphere.begin; i！= v_sphere.end（）; ++ i）
v_pPrimitives.push_back（& * i）;
...
//并调用v_pPrimitives [i] .IsPointInside（）; ??
v_pPrimitives [i] - > IsPointInside（）;
< head scratch>
我不能存储单个数组中的不同类型，但是我可以存储它们的指针，不行！？
Hi,
assume this situation:
class primitive
{
virtual void IsPointInside() =NULL;
NULL isn''t guaranteed to be 0, so
virtual void IsPointInside() = 0 ;
};
class sphere : public primitive
{ ... };
class tetrahedron : public primitive
{ ... };
std::vector<sphere > v_sphere;
std::vector<tetrahedron> v_tetrahedron;
// Can I do this:
std::vector<primitive*> v_pPrimitives;
for(i=v_sphere.begin; i!=v_sphere.end(); ++i)
v_pPrimitives.push_back(&*i);
...
// and call the v_pPrimitives[i].IsPointInside(); ??
v_pPrimitives[i]->IsPointInside();
<head scratch>
I can''t store different types in a single array, but I can store their
pointers, no!?
我会说你所存储的只是原始*，但由于那些
primitive *将指向类型派生自原始的对象，你可以使用通常的虚函数机制。
这真的没有什么不同
原语* p = new sphere（）;
p-> IsPointInside（）;
john
Well I would say that all you are storing is primitive*, but since those
primitive* will be pointing to objects whose type derives from primitive you
can use the usual virtual function mechanism.
It''s really no different to this
primitive* p = new sphere();
p->IsPointInside();
john
" Gernot Frisch" < Me@Privacy.net>在消息中写道
"Gernot Frisch" <Me@Privacy.net> wrote in message
假设这种情况：
类原语
{void void IsPointInside（）= NULL;
};
类球体：公共原语
{...};
类四面体：公共原语
{...};
std :: vector< sphere> v_sphere;
std :: vector< tetrahedron> v_tetrahedron;
//我可以这样做：
std :: vector< primitive *> v_pPrimitives;
for（i = v_sphere.begin; i！= v_sphere.end（）; ++ i）
i = v_sphere.begin（）
v_pPrimitives.push_back（& * i）;
...
//并调用v_pPrimitives [i] .IsPointInside（）; ??
Hi,
assume this situation:
class primitive
{
virtual void IsPointInside() =NULL;
};
class sphere : public primitive
{ ... };
class tetrahedron : public primitive
{ ... };
std::vector<sphere > v_sphere;
std::vector<tetrahedron> v_tetrahedron;
// Can I do this:
std::vector<primitive*> v_pPrimitives;
for(i=v_sphere.begin; i!=v_sphere.end(); ++i)
i=v_sphere.begin()
v_pPrimitives.push_back(&*i); ...
// and call the v_pPrimitives[i].IsPointInside(); ??
v_pPrimitives [i] - > IsPointInside（）
我现在没有看到任何问题。
Sharad
v_pPrimitives[i]->IsPointInside()
I don''t see any problem now.
Sharad
这真的没什么不同
primitive * p = new sphere（）;
p-> IsPointInside（）;
It''s really no different to this
primitive* p = new sphere();
p->IsPointInside();
一秒......然后，如果我有a
std :: vector< primitive> prims;
我可以push_back一个球体，这将保留所有额外的球体
特定信息吗？
我开始以为我从未真正了解过遗产......
One second... Then, if I have a
std::vector<primitive> prims;
can I push_back a sphere, which will keep all the additional sphere
specific information?
I get to thinking I never really understood about inheritances...
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