值分配到取消引用空指针 [英] Assign values to a dereferenced void pointer

问题描述

我在做C ++中的类，它支持任何类型的变量来帮助我在未来的项目中。问题是，当我试图分配一个值到无效* 变量，我得到的错误：无效* 不是指针到对象的类型。这里是code：

I'm doing a class in c++ that supports any kind of variable to help me in a future project. The thing is, when I try to assign a value to a void* variable, I get the error: void* is not a pointer-to-object type. Here is the code:

int main (void) {
    void* a;
    int x;
    a = malloc(sizeof(int));
    x = 120;
    ((int)(*a)) = x;
    printf("%d",((int)*a));
    free(a);
    system("pause");
    return 0;
}

我看到它就像我试图在分配为保留的内存块x的值。欲存储在x中的值被存储在一个存储块。可以any1能帮助我吗？

I see it like I am trying to assign the value of x in the memory block reserved for a. I want that the value stored in x be stored in the memory block of a. Can any1 help me?

推荐答案

首先，你必须投 A 到相应的指针类型和然后的去引用它。其次，用一个模板 - 这就是他们的东西。第三，malloc和free是baaaad，OK？别。如果你认为这是很好的code，你需要认真采取补救C ++。第四，这已经done- 的boost ::任何服务于这个目的。

Firstly, you must cast a to the appropriate pointer type and then de-reference it. Secondly, use a template- that's what they're for. Thirdly, malloc and free is baaaad, OK? Don't. If you think that this is good code, you need serious remedial C++. Fourthly, this is already done- boost::any serves this purpose.

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