Inheritance of interface is different from inheritance of implementation. Under public inheritance, derived classes always inherit base class interfaces.
Pure virtual functions specify inheritance of interface only.
Simple (impure) virtual functions specify inheritance of interface plus inheritance of a default implementation.
Non-virtual functions specify inheritance of interface plus inheritance of a mandatory implementation.
1
#include
<
iostream
>
2
#include
<
string
>
3
using
namespace
std;
4
5
class
Shape
6
{
7
public
:
8
virtual
void
draw()
const
=
0
;
9
virtual
void
error(
const
string
&
msg)
10
{
11
cout
<<
msg
<<
endl;
12
}
13
14
15
};
16
17
void
Shape::draw()
const
18
{
19
cout
<<
"
draw in Shape
"
<<
endl;
20
}
21
22
class
Rectangle:
public
Shape
23
{
24
public
:
25
virtual
void
draw()
const
26
{
27
cout
<<
"
draw in Rectangle
"
<<
endl;
28
}
29
};
30
31
int
main()
32
{
33
Rectangle
*
r
=
new
Rectangle();
34
r
->
draw();
35
r
->
Shape::draw();
36
cin.
get
();
37
return
0
;
38
}
转载于:https://www.cnblogs.com/zhtf2014/archive/2011/04/02/2003717.html
