ex1606.cpp

teach yourself C++ in 21 days 第五版

   #include <iostream>
   using namespace std;
   class Animal;
  
   void setValue(Animal& , int);
   
   class Animal
   {
     public:
       friend void  setValue( Animal&, int);
       int GetWeight()const { return itsWeight; }
       int GetAge() const { return itsAge; }
     private:
       int itsWeight;
       int itsAge;
  };
   
  void setValue(Animal& theAnimal, int theWeight)
  {
     theAnimal.itsWeight = theWeight;
  }
    
  int main()
  {
     Animal peppy;
     setValue(peppy,5);
     return 0;
  }