Question

In C++, is it possible to require a method in a base class to be overridden by all of its derived classes without making it a pure virtual method?

#include <iostream>
using namespace std;

class BaseClass{
    public:
    int printStuff(){ //find some way to require all derived classes to override this method
        cout << "Printing some stuff";
    }
};

class DerivedClass: public BaseClass{

};

int main(){
    cout << "Hello World!";
    return 0;
}

Answer 1

I know you said you didn’t want to use pure virtual functions, but you can use pure virtual functions and still give the method a definition if that’s what you are trying to do (not sure if you knew that already):

class BaseClass{
public:
    virtual int printStuff() = 0;
};

// give the pure virtual function an implementation
int BaseClass::printStuff() {
    cout << "Printing some stuff";
}

class DerivedClass: public BaseClass{
    // compiler error; DerivedClass must override printStuff
};

class DerivedClass2: public BaseClass{
public:
    int printStuff() {
        return BaseClass::printStuff(); // use the base class's implementation
    }
};