이제 클래스랑 포인터 배우는데 계속 값이 안나와요 ;; 어떻게 해야하죠 ??

#include<iostream.h>
#include<conio.h>
class BMI
{       public:
 double w;
 double h;


  void setWeight(double w)
  {this -> w = w;}
  void setHeight(double h)
  {this -> h = h;}
  double getBMI()
  {return w/(h/100*h*100);}

};

int main()
{
 BMI body;
 cout << "Input your weight and height" << endl;
 double x,y;
 body.w = x;
 body.h = y;
 cin >> x ;
 cin >> y ;
 double a = body.getBMI();

 if(a<18.5)
 {
  cout << "LOW obesity" << a << endl;
 }

 else if(18.5<a<23)
 {
  cout << "RIGHT obesity" << a << endl;
 }

 else if(23<a<25)
 {
  cout << "HEAVY obesity" << a << endl;
 }

 else if(30<a)
 {
  cout << "V.HEAVY obesity" << a << endl;
 }


 getch();
 return 0;

}