2_3_symb_diff

#include <iostream>
using namespace std;

class Expression {
public:
virtual ~Expression(){}
virtual Expression *diff()=0;
virtual void print()=0;
};


class Number:public Expression{
int Num;
public:
Number(int n):Num(n){}
Expression *diff(){return new Number(0);}
void print (){
    cout<<Num;
}
};
class Variable : public Expression{
char Var;
public:
Variable(char v):Var(v){}
Expression *diff(){return new Number(1);}
void print (){
    cout << Var;
}
};


class Add : public Expression{
Expression *x1;
Expression *x2;
Expression *Add1;
Expression *Add2;
public:
Add(Expression *Add1,Expression *Add2):x1(Add1),x2(Add2){};
Expression *diff(){return new Add(x1->diff(),x2->diff());}
void print (){
cout<<"(";
    x1->print();
    cout<<"+";
    x2->print();
    cout<<")";
}
};

class Sub :public Expression{
    Expression *x1;
    Expression *x2;
    public:
    Sub(Expression *Sub1,Expression *Sub2):x1(Sub1),x2(Sub2){}
    Expression *diff(){return new Sub(x1->diff(),x2->diff()); }
    void print (){
    cout<<"(";
        x1->print();
        cout<<"-";
        x2->print();
        cout<<")";
    }
};

class Mul : public Expression{
    Expression *x1;
    Expression *x2;
    public:
    Mul(Expression *Mul1,Expression *Mul2):x1(Mul1),x2(Mul2){}
    Expression *diff(){return new Add(new Mul(x1->diff(),x2),new Mul(x1,x2->diff())); }
    void print (){
        x1->print();
        cout<<"*";
        x2->print();
    }
};

class Div : public Expression{
    Expression *x1;
    Expression *x2;
public:
    Div (Expression *Div1,Expression *Div2) :x1 (Div1),x2 (Div2){}
    Expression *diff (){ return new Div(new Sub(new Mul (x2,x1->diff ()),new Mul (x1,x2->diff ())),new Mul(x2,x2)); }
    void print (){
        x1->print ();
        cout << "/";
        x2->print ();
    }
};

int main (){
setlocale(LC_ALL,"Ru");
Expression *a=new Add(new Variable('x'),new Number(45));
cout<<"Дифференциал суммы  ";
a->print();
cout<<"  =  ";
Expression *da=a->diff();
da->print();
cout<<endl;

Expression *s=new Sub(da, new Variable('k'));
cout<<"Дифференциал разности  ";
s->print();
cout << "  =  ";
Expression *ds=s->diff();
ds->print();
cout<<endl;

Expression *m=new Mul(new Add(new Number(1),new Variable('x')),new Variable('y'));
cout<<"Дифференциал произведения  ";
m->print();
cout << "  =  ";
Expression *dm=m->diff();
dm->print();
cout<<endl;

Expression *d = new Div (new Number(1),new Variable ('y'));
cout << "Дифференциал частного  ";
d->print ();
cout << "  =  ";
Expression *dd = d->diff ();
dd->print ();
cout << endl;

system("pause");
return 0;
}