1 #include<stdio.h>
 2 int add(int a,int b )
 3 {
 4     return a + b;
 5 }
 6 int sub(int a,int b )
 7 {
 8     return a - b;
 9 }
10 int mul(int a,int b )
11 {
12     return a * b;
13 }
14 int div(int a,int b )
15 {
16     return a / b;
17 }
18 int calc(int x,int y, int (*funp)(int,int))//上面的加减乘除函数就是回调函数，可以被形参中函数指针funp直接调用
19 {
20     int value = 0;
21     value = funp(x, y);
22     return value;
23 }
24 int main(int argc, const char *argv[])
25 {
26     int m = 20,n = 10;
27     int ret = 0;
28     
29     ret = calc(m,n,add);
30     ret = calc(m,n,sub);
31     printf("%d\n", ret);
32     
33     return 0;
34 }