5-4-1.cpp

学习c++的ppt

#include <iostream.h>
class  watermelon {
     private:
         float  weight;
         static float   total_weight;      //  静态数据成员
         static int     total_number;     //  静态数据成员
    public:
         watermelon(float w)  {
               weight = w;
               total_weight += weight;
               total_number ++;
         }
         ~watermelon()  {
               total_weight -= weight;
               total_number --;
         }
         void  display()  { cout<<"瓜重为："<<weight<<endl;  }
         static  void  total_display()  {
               cout<<"总瓜重为："<<total_weight<<endl;
               cout<<"总数量为："<<total_number<<endl;   }
};
float  watermelon::total_weight = 0;  //  静态成员数据初始化
int  watermelon::total_number = 0;
void main()
{     watermelon  w1(3.5f);
      w1.display();
      watermelon::total_display();
      watermelon  w2(6.3f);
      w2.display();
      watermelon::total_display();
      watermelon  w3(5.6f);
      w3.display();
      watermelon::total_display();
      w2.~watermelon();
      watermelon::total_display();
	  watermelon *p;
}