函数指针的简单应用

 
 1 int strcpy1(char *brr, char *crr)
 2 {
 3         int i=0;
 4         while(*(crr+i))
 5         {
 6                 *(brr+i) = *(crr+i);
 7                 i++;
 8         }
 9 
10         *(brr+i) = ‘\0‘;  //写到了*(crr+i)造成段错误
11 }
12 
13 int main()
14 {
15         int i;
16         char *arr = "hello!";
17         char data[1024] = {0};
18 
19         int (*p)(char *, char *) = strcpy1;
20         p(data, arr);
21 
22         printf("%s \n", data);
23 }

 1 #include <stdio.h>
 2 
 3 char * strcpy1(char *brr, char *crr)
 4 {
 5         int i=0;
 6         while(*(crr+i))
 7         {
 8                 *(brr+i) = *(crr+i);
 9                 i++;
10         }
11 
12         *(brr+i) = ‘\0‘;  //写道了*(crr+i)
13         return brr;
14 }
15 
16 int main()
17 {
18         int i;
19         char *arr = "hello!";
20         char data[1024] = {0};
21 
22         char *(*p)(char *, char *) = strcpy1;
23         char *red = p(data, arr);
24 
25         printf("%s \n", red);
26 }

#include <stdio.h>
#include <string.h>

char *fox(char *dest, char *src)
{
        int i, j;
        for(i=strlen(src)-1, j=0;i>=0; i--,j++)//sizeof(src)是四个字节，src是指针
        {
                *(dest+j) = *(src+i);
        }

        *(dest+j) = ‘\0‘;
        return dest;
}

int main()
{
        char *p = "hello!";

        char data[1024] = {0};

        char *(*fp)(char *, char *);
        fp = fox;
        char *red = fp(data, p);

        printf("%s \n", red);
}