函数指针

函数也有地址

#include <stdio.h>
void func(void);

int main(void)
{
   int i = 3;
   printf("i resides at %p\n", &i);
   printf("func() resides at %p\n", &func);
   printf("main() resides at %p\n", &main);
   return 0;
}


void func(void)
{
   printf("hello world\n");
}

函数指针：
以下为转载：

#include <stdlib.h>
#include <stdio.h>

void fun(int); /* 函数声明 */
int main(void)
{
    int x = 6;
    void (*p)(int); /* 定义函数指针变量 */
    p = &fun; /* 将fun函数的首地址赋给函数指针变量p*/
    fun(x); /* 直接调用fun函数 */
    (*p)(x); /* 通过函数指针变量p调用fun函数 */
    return 0;
}

void fun(int x) /* 函数定义 */
{
  printf("%d\n", x);
}

函数指针的应用：

#include "stdio.h"
#include "string.h"

#define CMD_COUNT (sizeof (cmd) / sizeof (cmd[0]))

/* Command definitions structure. */
typedef struct scmd
{
   char val[8];
   void (*func)(char *par);//函数指针,它指向 "void function_name(char *par)"这种形式的函数
} SRAM;

static void cmd_capture (char *par)
{
    printf(par);
}

static void cmd_type (char *par)
{
    printf(par);
}
static void cmd_rename (char *par)
{
    printf(par);
}

static void  cmd_copy (char *par)
{
    printf(par);
}

static void cmd_delete(char *par)
{
    printf(par);
}

static void cmd_dir (char *par)
{
    printf(par);
}

static void cmd_format (char *par)
{
    printf(par);
}

static const SRAM cmd[] = {
   "CAP", cmd_capture,
   "TYPE", cmd_type,
   "REN", cmd_rename,
   "COPY", cmd_copy,
   "DEL", cmd_delete,
   "DIR", cmd_dir,
   "FORMAT", cmd_format};

int main(void)
{
    char * str = "CAP";
    if(strcmp (str, cmd[0].val) == 0 )
    {
        printf("ok\n");
    }
    else
    {
        printf("no\n");
    }
    cmd[0].func("china!!!\n");
}