C++ how to replace constructor switch?

Question

I would like to replace big switch with something more elegant.

class Base
{
public:
  Base(void*data, int size);
  virtu         


        

Answer 1

You can use a simple factory method to create objects by required type and constructor parameters as in following example. Don't forget the virtual destructor when using inheritance and virtual functions.

#include 

class Base
{
public:
    Base(void* data, int size) {};
    virtual ~Base() {}
    virtual void Something() = 0;
};

class A : public Base
{
public:
    A(void* data, int size) : Base(data, size) {}
    void Something() override {};
};

class B : public Base
{
public:
    B(void* data, int size) : Base(data, size) {}
    void Something() override {};
};

Base* MyFactory(char type, void* data, int size)
{
    switch (type)
    {
        case 'a': return new A(data, size);
        case 'b': return new B(data, size);
        default:
            return nullptr;
    }
}

int main()
{
    std::unique_ptr obj1(MyFactory('a', nullptr, 1));
    obj1->Something();
    std::unique_ptr obj2(MyFactory('b', nullptr, 1));
    obj2->Something();
}