//函数指针
// void (*pf)(int) 名为pf,指向一个返回值为空，形参列表为int的函数指针
#include <stdio.h>
typedef struct Astruct
{
int _a; //成员变量
void(*pf1)(); //成员函数指针
int (*pf2)();
}*Astr;
int print1()
{
return 0;
}
int print2()
{
return 1;
}
void initastr(Astr str,int a)
{
str->_a = a;
str->pf1 = print1;
str->pf2 = print2;
printf("%d\n", *(str->pf1));
printf("%d\n", *(str->pf2));
}
int main()
{
Astr aa = (Astr) malloc(sizeof(int)*4);
initastr( aa, 3);
printf("%d\n", aa->_a);
return 0;
}
继承
typedef struct A
{
int _a;
}A;
typedef struct B
{
A a;
int _b;
}B;
函数指针 多态
#include <stdio.h>
struct A
{
int _a;
void(*print) (void *p);//函数指针
};
struct B
{
struct A Pa; //包含一个A类的对象 Pa
};
void printpa(void * p)
{
if (p == NULL)
return;
printf("call A\n");
}
void printpb(void * p)
{
if (p == NULL)
return;
printf("call B\n");
}
void print_F(void* p)
{
if (p == NULL)
return;
struct A* pa = (struct A*)p;
pa->print(p);
}
int main()
{
struct A a;
struct B b;
a.print = printpa; //A 中的函数指针指向函数
b.Pa.print = printpb;//B通过A的对象的函数指针指向的函数
print_F(&a);
print_F(&b);
return 0;
}
实现多态
#include <stdio.h>
typedef void (*Fun)(); // 定义一个函数指针
struct A{
Fun fun;
int a;
};
struct B{
A a;
int b;
};
void fa(){
printf("A fun called ...\n");
}
void fb(){
printf("B fun called ...\n");
}
int main(){
A a;
a.fun = fa;
B b;
b.a.fun = fb;
A* p = &a;
p -> fun();
// p = (A*)&b; // 需要强转
// p -> fun();
return 0;
}
