simple_class_factory

main.cpp

#include <vector>
#include <iostream>
#include <functional>
#include <unordered_map>

using namespace std;

struct Base{ virtual void print() = 0; };
struct A : public Base{ void print() override { cout << "A" << endl; } };
struct B : public Base{ void print() override { cout << "B" << endl; } };
struct C : public Base{ void print() override { cout << "C" << endl; } };

Base* createA(){ return new A(); }
Base* createB(){ return new B(); }
Base* createC(){ return new C(); }

int main()
{
    vector<Base*> v;
    unordered_map<char, function<Base*(void)>> funcs{
        {'A', createA},
        {'B', createB},
        {'C', createC},
    };
    
    while(true){
        char input;
        cin >> input;
        if(funcs.contains(input)){
            Base* newPtr = funcs[input]();
            v.push_back(newPtr);
        }else if(input == 'q'){
            break;
        }
    }
    
    cout << "--- vector ---" << endl;
    for(auto& e: v){
        e->print();
    }
    
    return 0;
}