j*******e
发帖数: 674 | 1 源程序：
#include
class A
{
public:
virtual void h()const{ printf("A::h() const\n");}
virtual void h(){ printf("A::h() non-const\n");}
};
class C: public A
{
public:
virtual void h(){ printf("C::h() non-const\n");}
};
int main()
{
C obj;
C* p1 = &obj;
const C* p2 = p1;
A* p3 = (A*)p1;
const A* p4 = p3;
p1->h();
//p2->h(); ///// this line will cause compile fail!!! but why?
p3->h();
p4->h();
return 0;
}
输出结果：
C::h() non-const
C::h() non-const
A::h() const
问题：
为 |
t****t
发帖数: 6806 | 2 add:
use A::h;
in class C
【在 j*******e 的大作中提到】
: 源程序：
: #include
: class A
: {
: public:
: virtual void h()const{ printf("A::h() const\n");}
: virtual void h(){ printf("A::h() non-const\n");}
: };
: class C: public A
: {
|
j*******e
发帖数: 674 | 3 Is "use" a keyword in C++?
Please explain in more detail.
【在 t****t 的大作中提到】
: add:
: use A::h;
: in class C
|
j*******e
发帖数: 674 | 4 you mean "using A::h"?
It works, but why is that necessary?
【在 t****t 的大作中提到】
: add:
: use A::h;
: in class C
|
t****t
发帖数: 6806 | 5 yeah, i meant "using"
sorry, was writing perl these days, mixed up
【在 j*******e 的大作中提到】
: you mean "using A::h"?
: It works, but why is that necessary?
|
F*****n
发帖数: 1552 | 6 This is called "Name Hiding".
virtual void h()const is hided by void h() in class C.
【在 j*******e 的大作中提到】
: 源程序：
: #include
: class A
: {
: public:
: virtual void h()const{ printf("A::h() const\n");}
: virtual void h(){ printf("A::h() non-const\n");}
: };
: class C: public A
: {
|
d*******d
发帖数: 2050 | 7 in class C, you have redefined h(), therefore, all the h() in the base class
, no matter what the signatures are, are hiddin by the new h(). Then, a cons
t object can only call a const function......
【在 j*******e 的大作中提到】
: 源程序：
: #include
: class A
: {
: public:
: virtual void h()const{ printf("A::h() const\n");}
: virtual void h(){ printf("A::h() non-const\n");}
: };
: class C: public A
: {
|
