c函数指针

#include <stdio.h>

void echo(void) {
    printf("===========echo===================\n");
}

void echo1(void) {
    printf("===========echo1===================\n");
}

long sum(int a,long b){
    return a+b;
}


int main(){

    // 定义函数指针
    void (*p) (void);

    long (*p1) (int,long);

    // void *func(int *a)
    void *(*p3)(int *);

    p = echo;
    p();
    p = echo1;
    p();

    p1 = sum;
    long result = p1(5,100);
    printf("===========result=%d\n",result);

    return 1;
}