Passing member function to member object into template parameter - c++

Question

I am trying to create a class/struct that can take in a struct/class of different types that all have the function update().
I want to get the update() function and then put it in a vector as a pointer and then call it later, but I'm having trouble putting member function pointers into a vector, but I am having no problem putting 'classless' function pointers into the vector.
How can I put the member function pointers into the vector?
Here is my code
#include <vector>
#include <iostream>
#include <stdio.h>
using namespace std;
struct typeA
{
public:
int data = 0;
void update()
{
cout << "hello, my data is " << data << endl;
}
};
struct typeB
{
float data = 0;
void update()
{
cout << "hi, my data is " << data << endl;
}
};
class typeListTwo
{
typedef void(*updaterFunc)();
vector <updaterFunc> items;
public:
typeListTwo()
{
}
~typeListTwo()
{
items.~vector();
}
void addItem(updaterFunc newItem)
{
items.push_back(newItem); //This works
}
void doWork()
{
for (unsigned int funcIndex = 0; funcIndex < items.size(); funcIndex++)
{
items[funcIndex]();
}
}
};
class typeList
{
typedef void(*updaterFunc)();
vector <updaterFunc> items;
public:
typeList()
{
}
~typeList()
{
items.~vector();
}
template <class Item>
void addItem(Item newItem)
{
items.push_back(newItem.update); //But this does not?
//newItem.update(); //This also works by itself
}
void doWork()
{
for (unsigned int funcIndex = 0; funcIndex < items.size(); funcIndex++)
{
items[funcIndex]();
}
}
};
void aFunc()
{
cout << "123 hello" << endl;
}
void bFunc()
{
cout << "456 goodbye" << endl;
}
int main()
{
typeA aThing;
typeB bThing;
typeList listThings;
typeListTwo listThingsTwo;
aThing.data = 128;
bThing.data = -3.234;
listThings.addItem(aThing);
listThings.addItem(bThing);
listThings.doWork();
listThingsTwo.addItem(aFunc);
listThingsTwo.addItem(bFunc);
listThingsTwo.doWork();
return 0;
}

Answer 1

The way to go is to use std::function or use interface:
class typeList
{
std::vector<std::function<void()>> items;
public:
template <class Item>
void addItem(Item& item)
{
// Care: life time of item should be bigger than this instance
items.push_back([&](){ item.update(); });
}
void doWork()
{
for (auto& f : items)
{
f();
}
}
};