Define an abstract class shape, including name, number, gender, derived three classes, circle, rectangle, triangle

#include<iostream>
#include<math.h>
using namespace std;
 class shape {
 public:
      virtual double  Area()=0;
      virtual double Setshaape () = 0;
};

class Tri:public shape{
private:
    double a1,b1,c1;
public:
     double  Area();
     double Setshaape ();
     Tri(){};
};

 double Tri::Area(){
    if((a1+b1)>c1){
      double p=(a1+b1+c1)/2.0;
    return sqrt(p*(p-a1)*(p-b1)*(p-c1));
    }
    else{
        cout<<"This is not a triangle"<<endl;
    }
    }
double Tri :: Setshaape () {
cin>>a1>>b1>>c1;
}
class R:public shape{
private :
    double  len,win;
public:
    R(){}
     double  Area();
     double Setshaape ();
};
double R::Setshaape(){
cin>>len>>win;
}
 double R:: Area(){
    return len*win;
    }


class C:public shape{
 private :
    double r;
public:
    double  Area();
    double Setshaape ();
    C(){}
};
double C :: Setshaape () {
cin>>r;
}
double C::Area(){
  double p;
    p= r*r*3.1415;
   return p;
    }

class Total:public Tri,public R,public C{
 public:
     double show (Tri  t,R r,C c){
     return double( t.Area()+r.Area()+c.Area());
     }
};
intmain()
{
   cout<<"Please enter the three sides of the triangle"<<endl;
   Tri T;
  T.Setshaape ();
  cout<<T.Area()<<endl;
   cout<<"Please enter the side length of the rectangle"<<endl;
   R r;
   r.Setshaape ();
   cout<<r.Area()<<endl;
    cout<<"Please enter the radius of the circle"<<endl;
   C c;
   c.Setshaape ();
   cout<<c.Area()<<endl;
   Total T1;
   cout<<T1.show(T,r,c)<<endl;
    return 0;
}