如何将类对象分配给指针？

Question

如何使指针指向同一类的真实对象的内存位置？

Class A
{
    int num = 0;
    A(int n) {
        this->num = n;
    }
}

int main()
{
    A a(10);
    A * aPtr;

    // How do I make "aPtr" point at "a"?

    // something like
    // aPtr = a; (I know this wont work but what instead)
}

Answer 1

  

如何将“aPtr”指向“a”？

使用&（地址）运算符：

aPtr = &a;

Answer 2

使用地址运营商：

A * aPtr = &a;                 // assume that & is not overloaded

#include <memory>

A * aPtr = std::addressof(a);  // more general