#include"stdio.h"
#include"malloc.h"
void f(struct arr *j)
{
   
}
int main(void)
{
            struct arr
            {
                int a;
                struct arr *p;
            };
            struct arr *z,*x;
    z=(struct arr*)malloc(sizeof(struct arr));
    z->a=1,z->p=x;
    f(&z);
    return 0;
}

呵呵谢谢各位了