在同一内存地址的两个不同的值 [英] Two different values at the same memory address

问题描述

#include <iostream>
using namespace std;

int main() {
    const int N = 22;
    int * pN = const_cast<int*>(&N);
    *pN = 33;
    cout << N << '\t' << &N << endl;
    cout << *pN << '\t' << pN << endl;
}

输出

Output

22 0x22ff74

22 0x22ff74

33 0x22ff74

33 0x22ff74

在同一地址有两个不同的值？

Why are there two different values at the same address?

推荐答案

相同的地址？

Why are there two different datas at the same address?

没有。编译器允许优化任何提到的const，就好像你在其中编写了编译时的值一样。

There aren't. The compiler is allowed to optimize any mention of a const to be as though you had written its compile-time value in there.

请注意，编译器也允许生成代码，当你运行它时，擦除你的硬盘，如果你犯了棘手的技巧，如写入内存为const保留。

Note that the compiler is also allowed to generate code that erases your hard disk when you run it if you do nasty tricks like writing to memory reserved for consts.

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