程序代码：

#include <stdio.h>

int main(void) {
    int a = 10, *pa = &a, **ppa = &pa, *pb=(int *)&pa;
    
    printf("a = %d\t&a = %X\n", a, (unsigned)&a);
    printf("pa = %X\n", (unsigned)pa);
    printf("&pa = %X\n", (unsigned)&pa);
    printf("ppa = %X\t**ppa = %d\n", (unsigned)ppa, **ppa);
    printf("pb = %X\t**pb = %d\n", (unsigned)pb, **(int **)pb);

    return 0;
}