本文学习自狄泰软件学院 唐佐林老师的 C语言进阶课程，图片全部来源于课程PPT，仅用于个人学习记录

函数类型

实验-函数指针

#include <stdio.h>typedef int(FUNC)(int);int test(int i)
{return i * i;
}void f()
{printf("Call f()...\n");
}int main()
{FUNC* pt = test;//void(*pf)() = &f;void(*pf)() = (int *)0x00401340;//okprintf("pf = %p\n", pf);printf("f = %p\n", f);printf("&f = %p\n", &f);pf();(*pf)();printf("Function pointer call: %d\n", pt(2));return 0;
}/*output:
pf = 00401340
f = 00401340
&f = 00401340
Call f()...
Call f()...
Function pointer call: 4*/

实验-回调机制

#include <stdio.h>typedef int(*Weapon)(int);void fight(Weapon wp, int arg)
{int result = 0;printf("Fight boss!\n");result = wp(arg);printf("Boss loss: %d\n", result);
}int knife(int n)
{int ret = 0;int i = 0;for(i=0; i<n; i++){printf("Knife attack: %d\n", 1);ret++;}return ret;
}int sword(int n)
{int ret = 0;int i = 0;for(i=0; i<n; i++){printf("Sword attack: %d\n", 5);ret += 5;}return ret;
}int gun(int n)
{int ret = 0;int i = 0;for(i=0; i<n; i++){printf("Gun attack: %d\n", 10);ret += 10;}return ret;
}int main()
{fight(knife, 3);fight(sword, 4);fight(gun, 5);return 0;
}/*output:
Fight boss!
Knife attack: 1
Knife attack: 1
Knife attack: 1
Boss loss: 3
Fight boss!
Sword attack: 5
Sword attack: 5
Sword attack: 5
Sword attack: 5
Boss loss: 20
Fight boss!
Gun attack: 10
Gun attack: 10
Gun attack: 10
Gun attack: 10
Gun attack: 10
Boss loss: 50*/

小结

C语言中的函数都有特定的类型
可以使用函数类型定义函数指针
函数指针是实现回调机制的关键技术
通过函数指针可以在C程序中实现固定地址跳转