私有数据成员不用友元也可以从外部访问?
#include <string>
#include <iostream>
using namespace std;
class sales_item
{
public:
sales_item(){}
sales_item(std::string s, double price): isbn(s), price(price){}
~sales_item(){}
sales_item& operator+=(const sales_item&);
protected:
private:
std::string isbn;
double price;
};
sales_item& sales_item::operator +=(const sales_item &item)
{
price+=item.price;//item的price数据成员是私有的,为何编译不报错,而且运行很正常???
return *this;
}
int main(int argc, char *argv[])
{
sales_item item1("ABCD!!", 12.5), item2("EFGH", 22.5);
item1+=item2;//完全正常,不报错,而且price的值也相加了。
return 0;
}