一个地址，两个值

#include <stdio.h>int main(void){    const int a = 10;    *(int *)&a = 20;    if ( a == 20)        printf("a = 20\n");    printf("%d, %X\n", a, &a);;    printf("%d, %X\n",*(int *)&a,(int *)&a);    return 1;}

const关键字的详解

http://www.cnblogs.com/yc_sunniwell/archive/2010/07/14/1777416.html