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