定義:
class Shape
{
public:
//...
void moveTo(Point newLocation);
bool validate()const;
vritual bool draw() const=0;
//...
}:
class Circle: public Shape
{
//...
bool draw() const;
//...
};
void (Shape::*mf1)(Point ) = &Shape::moveTo;//指向類的成員函數的指針。
ReturnType (ClassName::*pFuncName)(paramList);
pFuncName定義了指向ClassName中的一組函數。這組函數的形式是返回值為ReturnType，函數列表為paramList.
ClassName的限定使得只有ClassName或派生自它的類的對象才能解引用這個函數指針。
1 #include"stdafx.h"
2 #include<stdio.h>
3 #include<stdlib.h>
4
5 class Base;
6 class Derived;
7 typedef long (Base::*PFunc)(long,long);
8
9 enum FuncType
10 {
11 ADD=1,
12 SUB,
13 DIV,
14 MUL,
15 };
16
17 typedef struct tagCallBackFunc
18 {
19 long funcType;
20 PFunc proc;
21 }COMMAND,*PCOMMAND;
22
23 class Base
24 {
25 public:
26
27 virtual PCOMMAND GetCommands(void);
28 static COMMAND command[];
29
30 long base_add(long a,long b){printf("in base_add()\n");return a+b;}
31 long base_sub(long a,long b){printf("in base_sub()\n");return a-b;}
32 long base_div(long a,long b){printf("in base_div()\n");return a/b;}
33 long base_mul(long a,long b){printf("in base_mul()\n");return a*b;}
34 };
35
36 COMMAND Base::command[]={
37 {ADD,(PFunc)&Base::base_add},
38 {SUB,(PFunc)&Base::base_sub},
39 {MUL,(PFunc)&Base::base_mul},
40 {DIV,(PFunc)&Base::base_div},
41 };
42 PCOMMAND Base::GetCommands()
43 {
44 return command;
45 }
46
47 class Derived:public Base
48 {
49 public:
50 Derived(void){}
51 ~Derived(void){}
52 virtual PCOMMAND GetCommands(void){return command;}
53
54 long add(long a,long b){printf("in add()\n");return a+b;}
55 long sub(long a,long b){printf("in sub()\n");return a-b;}
56 long div(long a,long b){printf("in div()\n");return a/b;}
57 long mul(long a,long b){printf("in mul()\n");return a*b;}
58
59 static COMMAND command[];
60 };
61
62 COMMAND Derived::command[]=
63 {
64 {ADD,(PFunc)&Derived::add},
65 {SUB,(PFunc)&Derived::sub},
66 {MUL,(PFunc)&Derived::mul},
67 {DIV,(PFunc)&Derived::div},
68 {0}
69 };
70
71
72
73 void test(Base *control,FuncType funcType,long operand1,long operand2)
74 {
75 PCOMMAND pCommand = control->GetCommands();
76 PCOMMAND pNowCommand=NULL;
77
78 for(long i=0;pCommand[i].funcType;++i)
79 {
80 if(funcType == pCommand[i].funcType)
81 {
82 pNowCommand = &pCommand[i];
83 break;
84 }
85 }
86
87 if(pNowCommand)
88 {
89 long res = (control->*pNowCommand->proc)(operand1,operand2);
90 printf("res=%d\n",res);
91 }
92 }
93
94 int main()
95 {
96 Derived *d =new Derived();
97 Base *b = (Base*)d;
98 test(b,ADD,1,2);
99
100 Base *bb = new Base;
101 test(bb,MUL,1,2);
102 delete bb;
103 delete d;
104 return 0;
105 }
第89行是對指向類成員函數的指針的解析。