I am trying to create a script that uses polymorphism to create a set of linking vectors within parent/child class structure. So far I have got the classes setup, but when trying to test the code I receive an error involving static assertion. When analysing the code line by line, I run into the error when I call 'vector.begin() & vector.end()'.
Here is the full script:
#include <iostream>
#include <vector>
using namespace std;
class A
{
public:
vector<vector<A *>> Container;
};
class B : A
{
};
class C : A
{
};
class D : A
{
};
int main()
{
A ABaseClass;
B b1, b2;
C c1, c2;
D d1, d2;
vector<B *> b_classes = {&b1, &b2};
vector<C *> c_classes = {&c1, &c2};
vector<D *> d_classes = {&d1, &d2};
ABaseClass.Container = {
{b_classes.begin(), b_classes.end()},
{c_classes.begin(), c_classes.end()},
{d_classes.begin(), d_classes.end()}};
}
Compiling gives this error:
error: static assertion failed: result type must be constructible from value type of input range
138 | static_assert(is_constructible<_ValueType2, decltype(*__first)>::value,
| ^~~~~
error: static assertion failed: result type must be constructible from value type of input range
note: 'std::integral_constant<bool, false>::value' evaluates to false
I have narrowed down the cause of the error to this section:
ABaseClass.Container = {
{b_classes.begin(), b_classes.end()},
{c_classes.begin(), c_classes.end()},
{d_classes.begin(), d_classes.end()}};
Following the root of the problem leads me to the file 'stl_uninitialized.h', and the line:
[138] static_assert(is_constructible<_ValueType2, decltype(*__first)>::value,
^~~~~
I have been trying to get the child classes to be tracked by the parents but I am unfamiliar with vectors and pointers so I am a bit stuck. Any help with moving forward would be greatly appreciated.
Upcast to a base class is ill-formed if the inheritance is not public. i.e
struct base {};
class derived : base {}; // private inheritance
int main(){
derived a;
auto & b = static_cast<base &>(a); // invalid
}
That's exactly what that last assignment expression is trying to do. You will need to inherit publically. i.e
class A
public:
vector<vector<A *>> Container;
};
class B : public A
{
};
class C : public A
{
};
class D : public A
{
};
EDIT: This is the answer originally cited:
class A
public:
vector<vector<A *>> Container;
};
struct B : A
{
};
struct C : A
{
};
struct D : A
{
};