QtDesignPatterns/commandpattern/interface.h

#include "stock.h"

class Order
{
public:
    Order(){}
    virtual ~Order(){}
    virtual void execute() = 0;
};

class BuyStock: public Order
{
public:
    BuyStock(Stock *stock) : stock(stock){}
    void execute()
    {
        stock->buy();
    }
private:
    Stock *stock;
};

class SellStock: public Order
{
public:
    SellStock(Stock *stock) : stock(stock){}
    void execute()
    {
        stock->sell();
    }

private:
    Stock *stock;
};