Класс Triangle, при вводе сторон и угла не выводит результат

#include <iostream>
#include <cmath>
//ГЎГ*çîâûé ГЄГ«Г*Г±Г±
class Triangle
{ protected:
    double a,b; //2 ñòîðîГ*Г»
    double u;   //óãîë
  public:
    Triangle(){}
    Triangle(double x, double y, double z): a(x), b(y), u(z){}
    virtual ~Triangle(){}
    virtual double S() = 0; //ïëîùГ*äü
    virtual double P() = 0; //ïåðèìåòð
};
class pryam : public Triangle //ïðÿìîóãîëüГ*ûé òðåóãîëüГ*ГЁГЄ
{
public:
    pryam(double x, double y, double z): Triangle(x, y, z){}
    pryam(){}
    double S(); //ïëîùГ*äü
    double P(); //ïåðèìåòð
 
};
double pryam::S()
{
  return 0.5*a*b*sin(u);//?
}
double pryam::P()
{
  double c = sqrt(a*a+b*b-2*a*b*cos(u));//?
  return a+b+c;//?
};
///////////////
class ravbedr : public Triangle
{
 
  public:
    ravbedr(double x, double y, double z): Triangle(x, y, z){}
    ravbedr(){}
     double S();
     double P();
};
double ravbedr::S()
{
    double c=2*a*sin(u/2); 
    double p=(a+b+c)/2;
    return sqrt(p*(p-a)*(p-b)*(p-c));
}
double ravbedr::P()
{
    double c=2*a*sin(u/2); 
    return a+b+c;
}
///////////////////
class ravstor : public Triangle
{
 public:
     ravstor(double x, double y, double z): Triangle(x, y, z){}
    ravstor(){}
     double S();
     double P();
};
double ravstor::S()
{
    return 0.43*a*a;
}
double ravstor::P()
{
    return 3*a;
}
/////////////////////////////
int main()
{
    Triangle *pt = NULL;
    int a, b, u;
    do
    {
        std::cout<< "Enter length of the first side: "; std::cin>> a;
        std::cout<< "Enter length of the second side: "; std::cin>> b;
        std::cout<< "Enter the angle between the sides: "; std::cin>> u;
    } while (a < 0 || b < 0 || u < 0 || u > 180);
    if (a == b)
    {
        if (u == 60) pt = new ravstor(a, b, u);
        else pt = new ravbedr(a, b, u);
    }
    else if(u == 90) pt = new pryam(a, b, u);
    if (pt == NULL) std::cout<< "Random triangle, count yourself, it's boring...";
    else std::cout<< "P = "<< pt->P()<< "\nS = "<< pt->S();
    delete pt;
    return 0; 
}