1.9. __________________________________________33

         ? 
  case       .  -
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  ,     case,   -
 case          case. 
,     .

-    C++ 
      .  ,   
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 .      . 
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  C++,   ,  shape  -
  .  ,      
,     :

  shapel.cpp

//shape     ()

class shape {
public:

virtual double area() = 0;     //  

//()

1 .

J /

class rectangle : public shape { //
public:

rectangle(double h, double w) :

height(h) , width(w){}

double area() {return (height * width);}
private:

double height, width;          //, 
^ .

class circle : public shape {    //
public:

circle(double r) : radius(r) { }

double area() {return(3.14159 * radius * radius);}
private:

double radius;                 //
};

      . 
 area ()    :

shape* ptr_shape;