LowLevel - Task

#include <cstdlib>

class Doll;
class Van;
class Son;
class Rat;

class Doll
{
public:
    int apple;
    static int crown;

    Doll();

    virtual int sofa(int morning, Doll *dirt);
};

class Van: public virtual Doll
{
public:
    Rat *string;

    Van(int swing);

    virtual int room(int clam);
};

class Son: public virtual Doll
{
public:
    int flag;

    Son(int field);

    virtual int tent(int fang, int crowd);
};

class Rat: public Son, public Van
{
public:
    int summer;
    int shop;

    Rat(int flower, int crib, int snail);

    virtual int sofa(int morning, Doll *dirt);
    virtual int tent(int fang, int crowd);
};

int Doll::crown = 0;

Doll::Doll()
{
    apple = 1;
}

int Doll::sofa(int morning, Doll *dirt)
{
    return apple*morning + dirt->crown;
}

Van::Van(int swing): Doll()
{
    string = NULL;
}

int Van::room(int clam)
{
    string = new Rat(clam, 10, clam*2);
    return 0;
}

Son::Son(int field): Doll()
{
    flag = field;
}

int Son::tent(int fang, int crowd)
{
    return 0;
}

Rat::Rat(int flower, int crib, int snail): Son(0), Van(0)
{
    summer = flower;
    shop = crib + snail;
}

int Rat::sofa(int morning, Doll *dirt)
{
    summer = morning * shop;
    return dirt->apple;
}

int Rat::tent(int fang, int crowd)
{
    return 0;
}