C ++：不能static_cast从double *到int * [英] C++: can't static_cast from double* to int*

问题描述

当我尝试使用static_cast将double *转换为int *时，会出现以下错误：

When I try to use a static_cast to cast a double* to an int*, I get the following error:

invalid static_cast from type ‘double*’ to type ‘int*’

p>

Here is the code:

#include <iostream>
int main()
{
        double* p = new double(2);
        int* r;

        r=static_cast<int*>(p);

        std::cout << *r << std::endl;
}

我理解在double和int之间转换会有问题，为什么在double *和int *之间转换有问题？

I understand that there would be problems converting between a double and an int, but why is there a problem converting between a double* and an int*?

推荐答案

除了指针， double * 和 int * 没有什么共同之处。你可以对任何不同结构的 Foo * 和 Bar * 指针类型说同样的话。

Aside from being pointers, double* and int* have nothing in common. You could say the same thing for Foo* and Bar* pointer types to any dissimilar structures.

static_cast 意味着源类型的指针可以被使用作为目标类型的指针，这需要一个子类型关系。

static_cast means that a pointer of the source type can be used as a pointer of the destination type, which requires a subtype relationship.

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