c++对象数组 计算问题

Question

用对象数组分别对三个销售员的销售员号、销售件数和销售单价赋值
Commodity com[3]={{101,5,23.5},{102,12,24.56},{103,100,21.5}};
现已知对购买十件以上者要打98折，要求每件商品的平均售价。

这样写为什么不对呢?? quantity和price我都放在了public里，discount是静态数据成员。求大神指教？？

Answer 1

程序已验证
#include
using namespace std;
class Commodity
{
private:
int num;
int quantity;
float price;
static float discount;
static float sum;
static int n;
public:
Commodity(int num,int q,float p);
~Commodity();//析构函数
static float average();//求平均售价函数声明
static void display();
};
float Commodity::discount=0.98;
float Commodity::sum=0;
int Commodity::n=0;
Commodity::Commodity(int num,int q,float p)
{
num=num;quantity=q;price=p;
n+=q;
sum+=q*p;
}
Commodity::~Commodity(){}
float Commodity::average()
{
if(n==0)return 0;
else return sum/n;
}
void Commodity::display()
{
cout<<"***n"<<n<<endl;//+=c1.quantity;
cout<<"总销售款:"<<sum<<"\t平均售价："<<average()<<endl;
}
int main()
{
Commodity c1(101,5,23.5),c2(102,12,24.56),c3(103,100,21.5);
c1.display();
c2.display();
Commodity::display();
}