Are array of pointers to different types possible in c++?

Question

Are array of pointers to different types possible in c++? with example please)

Answer 1

Usually if you want to have a collection of different "types" of pointers, you implement it in a way where they derive off a base class/interface and store a pointer to that base. Then through polymorphism you can have them behave as different types.

class Base
{
public:
    virtual void doSomething() = 0;
};

class A : public Base
{
    void doSomething() { cout << "A\n"; } 
};

class B : public Base
{
    void doSomething() { cout << "B\n"; } 
};

std::vector<Base*> pointers;
pointers.push_back(new A);
pointers.push_back(new B);

Answer 2

An array of pointers to void has already been mentioned. If you want to make it practical and useful, consider using an array (or, better, vector) of boost::any .

Answer 3

C++ is C with more stuff. So if you want to do it the C way, as above you just make an array of void pointers

void *ary[10];
ary[0] = new int();
ary[1] = new float();

DA.

If you want to do things the object oriented way, then you want to use a collection, and have all the things you going to be adding to the collection derive from the same base object class that can be added to the collection. In java this is "Object", C++ has no base object built in, but any collection library you use will have such a thing that you can subclass.

Answer 4

......如果你使用空格*，那很容易;-)

Answer 5

Yes. Two ways:

• Pointers to a base class type, which point to objects of types derived from that base type.
• Untyped void * pointers, which must be cast manually to the actual object types they point to.

The first approach is standard object-oriented programming.

The second approach is useful for low-level programming (eg, device drivers, memory management libraries, etc.), and is considered dangerous and suitable only for programmers who know exactly what they're doing. Obviously, it requires additional bookkeeping info to tell you what each pointer's real type is.

Answer 6

Yes; just cast your pointers in the array to whatever type you want them to refer to.

Alternately, you could make your array an array of a union (with the union elements being the differing pointer types).

Answer 7

#include <stdio.h>

int main(void)
{
  void * ptr[2];
  int *a;
  int b;

  ptr[0] = "[0] = \"This is a string & c does it better\", [1] = ";
  *a = 2;
  ptr[1] = a;
  b = *((int *) ptr[1]);
  printf("%s",  (char *) ptr[0] );
  printf("%i\n", b );

  return 0;
}