1.函数指针
#include <stdio.h>
int add(int a, int b)
{
return a + b;
}
int sub(int a, int b)
{
return a - b;
}
int main(void)
{
int (*p) (int, int);
p = add;
printf("res is %d\n", p(5, 5));
p = sub;
printf("res is %d\n", p(5, 5));
return 0;
}
2.指针函数
#include <stdio.h>
#include <stdlib.h>
char *alloc_space(int size)
{
return (char *)malloc(size);
}
int main(void)
{
char *p;
p = alloc_space(100);
printf("res is %d\n", p[99]);
return 0;
}
3.void *
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
int main(void)
{
void *p1;
char *p2;
int *p3;
printf("size is %ld\n",sizeof(p1));
printf("size is %ld\n",sizeof(p2));
printf("size is %ld\n",sizeof(p3));
p1=malloc(4);
memset(p1,0x1,4);
p2=p1;
printf("value is 0x%x\n",*p2);
p3=p1;
printf("value is 0x%x\n",*p3);
return 0;
}
size is 8
size is 8
size is 8
value is 0x1
value is 0x1010101