Avoiding "Pure Virtual Function Call" in Derived Class C++

Question

I'm reasonably new to C++ so I'd like to apologize if the level of this question is a little below the usual standards here - I'm trying to get several classes to inherit from a base class which has a virtual function definition, then I'd like to create an array of MainClass* which can include all of the derived classes in order to output the derived + defined virtual function. I receive the Error "R6025: pure virtual function call" - I don't know why, I was assuming that - when called - the updated definition of that function from the child classes was used. Here's my code: Base: ``` class mitarbeiter { public: mitarbeiter(string name, int nummer); ~mitarbeiter(void); virtual void einkommen() = 0; protected: string name; int nummer; }; ``` Derived1: ``` #include "mitarbeiter.h" class lohnempfaenger : public mitarbeiter { public: lohnempfaenger(int stundenlohn, int anzahlStunden, string name, int nummer); ~lohnempfaenger(void); void einkommen(); private: int stundenlohn; int anzahlStu…

Accepted Answer

Now you've shown us how you actually initialise the pointer, here is the problem:

```
mitPtr[0] = &angestellter(/*values...*/);
```

That points to a temporary object, which is destroyed at the end of the statement. Using the pointer afterwards will give undefined behaviour.

You'll need a non-temporary variable to point to:

```
angestellter a(/*values...*/);
mitPtr[0] = &a;
```

or perhaps a dynamically allocated object:

```
mitPtr[0] = new angestellter(...);
```

In that case, don't forget to delete it; and don't forget to give the base class a virtual destructor so it can be deleted. You might consider using a smart pointer to delete it for you; `std::unique_ptr` would be ideal.

Avoiding "Pure Virtual Function Call" in Derived Class C++

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