why const object can be changed?

From: Yong (netclassic_at_sina.com)
Date: 10/05/04 

Date: Tue, 5 Oct 2004 21:20:04 +0800

Hello,

I have some questions in using keyword "const".Just look the code below

#include <stdio.h>
int main(){
    const int c = 12;
    int *p=(int *)&c;
    *p = 3;
    printf("%d,%d",c,*p);
    return 0;
}

the output would be:
12,3 //why?? *p should be same as c, but...

But if I rewrite my code in this way
#include <stdio.h>
const int c = 12;
int main(){
    //const int c = 12;
    int *p=(int *)&c;
    *p = 3;
    printf("%d,%d",c,*p);
    return 0;
}

there will be a runtime error in line : *p=3 .

I compiled it with g++ and vc7.1 and the results are same.

My question is why the value of *p can be changed in the former condition
but not in the latter.

Thanks

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