 TValue.   ,  C++  - GetValue()
 ,      . 
        ,  GetVa()  
-.   -    
  (  ,     
).   -    
( ).  -     
       . 

     

    Borland C++    -,   
          
.     . 

      14.4   TValue  TMult,     
,    .    GetValue()   
-.        DOS 
 EasyWin-. 

     14.4.  VIRTUAL,CPP (   -) 

   1.   #include <iostream.h> 
   2. 
   3:	class TValue { 
   4:	protected: 
   5:	   int value; 
   6:	public: 
   7:	   TValue(int n) { value = n; }                     
   8:	   virtual int GetValue(void) { return value; }
   9:	};                      
   10:
   11:	class TMult:   public TValue { 
   12:	protected:               
   13:	   int multiplier; 
   14:	public:
   15:	   TMult(int n,  int m): TValue(n) { multiplier = m;   } 
   16:	   virtual int *GetValue(vpid)  {  return value * multiplier;   } 
   17:	}; 
   18:
   19:	main()
   20:	{ 
   21:	   TValue -basep;
   22:
   23:	basep = /few TValue(10);   
   24:	cout  basep->GetValue()   '\n';    //  10 
   25:	delete basep; 
   26:	 
   27:	basep = new TMult(10,  2);         .   // !!! 
   28:	cout  basep->GetValue()  '\n';    // !!!  20 
   29:	delete basep;
   30:	
   31:           return 0; 
   32:         }         

      8  16   GetValue()  
  virtual.    ,   
- GetValue()    .  
    - GetValue()
   .     
-, C++       .   , 
    ,    .  
        
,      . 
     -   ,    
-. ,   , -  
 .  ,       
GetValue()  -      TMult
( 11-17)   ,      TValue ( 3-9). 
,     virtual     
   . 
       VIRTUAL  ,      10 
 20      - GetValueO.   
21   basep   TValue.   23  new  
  TValue,    10 ( 24), 


    354  III.   ANSI C++ 
