**pointer 和 &pointer 作为函数参数有什么区别？

Question

#include <stdio.h>

void initialize(int **);
void control(int **);

int main(void){

    int *pointer;
    printf("%p\n",pointer);
    initialize(&pointer);
    printf("%p\n",pointer);
    control(&pointer);

    return 0;
}

void initialize(int **point){
    printf("%p\n",point);
    *point = NULL;
    printf("%p\n",point);
}
void control(int **point){
    if(*point == NULL)
        printf("hi");
    else
        printf("good bye");
}

There is no problem in the code above, but when I change it like this:

int **pointer;
printf("%p\n",pointer);
initialize(pointer);
printf("%p\n",pointer);
control(pointer);

It doesn't work properly. I wonder why it doesn't work same as &pointer .

Answer 1

我试过你的代码，它给出了分段错误，这应该是由空指针引起的，当空指针的指针在 initialize() 函数中被赋值为 null 时。