商品折扣问题

#include <iostream>using namespace std;class Product{public:Product(int m,int q,float p):num(m),quantity(q),price(p){};void total();static float average();static void display();private:int num;int quantity;float price;static float discount;static float sum;//销售总额static int n;//销售件数};void Product::total()//计算销售总额，统计件数{float rate=1.0;if(quantity>10)rate=0.98*rate;sum=sum+quantity*price*rate*(1-discount);n=n+quantity;}void Product::display(){cout<<"销售总额为 "<<sum<<",每件的平均售价为 ";cout<<average()<<endl;}float Product::average()//静态成员函数只能调用静态数据成员{return(sum/n);}float Product::sum=0;int Product::n=0;float Product::discount=0.05;int main(){Product pro[3]={  Product(101,5,23.5),Product(102,12,24.56),Product(103,100,21.5) };for(int i=0;i<3;i++)pro[i].total();Product::display();return 0;}