sh

#include <iostream>
#include <string>
#include <cmath>
using namespace std;
class human{
protected:
    string name,surname;
    int age;
public:
    human(string x,string y){
        name=x;
        surname=y;
        age=0;
    }
    human(string x,string y,int age_1){
        name=x;
        surname=y;
        age=age_1;
    }
    void say_hello(){
        if(age>0){
            cout<<"hello my name is "<<name<<"  "<<surname<<endl<<age<<" years old"<<endl;
        }
        else{
          cout<<"hello my name is "<<name<<"  "<<surname<<endl;
        }

    }
};

class worker : public human{
protected:
    float salary;
    string jobname;
public:
    worker(string x, string y, float z,string job) : human(x, y), salary(z),jobname(job){}
    worker(string x, string y,int age_1, float z,string job) : human(x, y, age_1), salary(z),jobname(job){}
    void say_hello(){
        human::say_hello();
        cout << "\t  salary - "<<salary<<"  job name is "<<jobname << endl;
    }
};
class animal{
public:
    virtual void print()=0;
};
class cat:public animal{
public:
    void print(){
        cout<<"cat"<<endl;
    }
};
class dog:public animal{
public:
    void print(){
        cout<<"dog"<<endl;
    }
};

class shape{
public:
    virtual float S() = 0;
};

class square:public shape{
public:
    float a,s;
    square(float x){
        a=x;
    }
   float S(){
       s=a*a;
       return s;
   }
};
class rectangle:public shape{
public:
    float a,b,s;
    rectangle(float a1,float b1):a(a1),b(b1){
    }
    float S(){
        s=a*b;
        return s;
    }
};
class circle:public shape{
public:
    float p=3.1415;
    float r;
    circle(float r1):r(r1){
    }
    float S(){
        float s=p*(r*r);
        return s;
    }
};
class triangle:public shape{
public:
    float a,b,c;
    triangle(float a1,float b1,float c1):a(a1),b(b1),c(c1){}
    float S(){
        float p=(a+b+c)/2;
        float s=sqrt(p*(p-a)*(p-b)*(p-c));
        return s;
    }
};

int main()
{
    shape *a=new square(5);
    cout << a->S() << endl;
    shape *b=new rectangle(5,10);
    cout<< b->S()<<endl;
    shape *c=new circle(12);
    cout<< c->S()<<endl;
    shape *t=new triangle(3,4,5);
    cout<<t->S()<<endl;
}