initialize a class object in the malloc address?
c++
Solution
To instantiate a class instance at a specific address you need to use placement new.
#include <new>
#include <stdlib.h>
class A
{};
int main()
{
void *p = malloc(100);
A* a = new(p) A();
a->~A(); // call destructor explicitly
free(p);
}
Note that the destructor must be invoked explicitly when using placement new.
Problem
say we have ``` Class A{}; int *p = malloc(100); A a; //default constructor in use *p = A; (question???) ``` how to initialize an object of type A on alloc memory p?