我如何将多个类存储在一个变量中，也许是一个列表？ 或矢量？ 多态性

Question

I'm still somewhat new to c++ and I'm unsure about creating different instances within a list. In my program I have multiple classes inheriting from the base class:

class Foo{

}

class Bar : public Foo {

}

class Fin : public Foo {

}

The problem that I am facing is I need to replace one with another in case one is destroyed. For example:

for (int i = 0; i < list/vector/? ; i++){
    if (bar_i[i].destroyed()){
        Fin fin_i = new Fin(); // in place of Bar
    }
}

which would then take the Bar(s) spot. What could I use to create a list, vector, or whatever to create the instances of multiple classes?

Answer 1

You can't store different types in the standard containers (a standard container requires all elements to be of the same type).

However, you can use polymorphism and store pointers to a parent (common) type.

You may want to rethink your design and move common methods and members to a parent type.

Edit 1: Example implementation

std::vector<Foo *> container;
for (unsigned int i = 0; i < 6; ++i)
{
  if (i & 1)
  {
    container.push_back(new Bar);
  }
  else
  {
    container.push_back(new Fin);
  }
}
  for (unsigned int i = 0; i < 6; ++i)
  {
    container[i]->Common_Operation();
  }